what does a systematic literature review do

Jump to navigation

Cochrane Training

Chapter 1: starting a review.

Toby J Lasserson, James Thomas, Julian PT Higgins

Key Points:

• Systematic reviews address a need for health decision makers to be able to access high quality, relevant, accessible and up-to-date information.
• Systematic reviews aim to minimize bias through the use of pre-specified research questions and methods that are documented in protocols, and by basing their findings on reliable research.
• Systematic reviews should be conducted by a team that includes domain expertise and methodological expertise, who are free of potential conflicts of interest.
• People who might make – or be affected by – decisions around the use of interventions should be involved in important decisions about the review.
• Good data management, project management and quality assurance mechanisms are essential for the completion of a successful systematic review.

Cite this chapter as: Lasserson TJ, Thomas J, Higgins JPT. Chapter 1: Starting a review. In: Higgins JPT, Thomas J, Chandler J, Cumpston M, Li T, Page MJ, Welch VA (editors). Cochrane Handbook for Systematic Reviews of Interventions version 6.4 (updated August 2023). Cochrane, 2023. Available from www.training.cochrane.org/handbook .

1.1 Why do a systematic review?

Systematic reviews were developed out of a need to ensure that decisions affecting people’s lives can be informed by an up-to-date and complete understanding of the relevant research evidence. With the volume of research literature growing at an ever-increasing rate, it is impossible for individual decision makers to assess this vast quantity of primary research to enable them to make the most appropriate healthcare decisions that do more good than harm. By systematically assessing this primary research, systematic reviews aim to provide an up-to-date summary of the state of research knowledge on an intervention, diagnostic test, prognostic factor or other health or healthcare topic. Systematic reviews address the main problem with ad hoc searching and selection of research, namely that of bias. Just as primary research studies use methods to avoid bias, so should summaries and syntheses of that research.

A systematic review attempts to collate all the empirical evidence that fits pre-specified eligibility criteria in order to answer a specific research question. It uses explicit, systematic methods that are selected with a view to minimizing bias, thus providing more reliable findings from which conclusions can be drawn and decisions made (Antman et al 1992, Oxman and Guyatt 1993). Systematic review methodology, pioneered and developed by Cochrane, sets out a highly structured, transparent and reproducible methodology (Chandler and Hopewell 2013). This involves: the a priori specification of a research question; clarity on the scope of the review and which studies are eligible for inclusion; making every effort to find all relevant research and to ensure that issues of bias in included studies are accounted for; and analysing the included studies in order to draw conclusions based on all the identified research in an impartial and objective way.

This Handbook is about systematic reviews on the effects of interventions, and specifically about methods used by Cochrane to undertake them. Cochrane Reviews use primary research to generate new knowledge about the effects of an intervention (or interventions) used in clinical, public health or policy settings. They aim to provide users with a balanced summary of the potential benefits and harms of interventions and give an indication of how certain they can be of the findings. They can also compare the effectiveness of different interventions with one another and so help users to choose the most appropriate intervention in particular situations. The primary purpose of Cochrane Reviews is therefore to inform people making decisions about health or health care.

Systematic reviews are important for other reasons. New research should be designed or commissioned only if it does not unnecessarily duplicate existing research (Chalmers et al 2014). Therefore, a systematic review should typically be undertaken before embarking on new primary research. Such a review will identify current and ongoing studies, as well as indicate where specific gaps in knowledge exist, or evidence is lacking; for example, where existing studies have not used outcomes that are important to users of research (Macleod et al 2014). A systematic review may also reveal limitations in the conduct of previous studies that might be addressed in the new study or studies.

Systematic reviews are important, often rewarding and, at times, exciting research projects. They offer the opportunity for authors to make authoritative statements about the extent of human knowledge in important areas and to identify priorities for further research. They sometimes cover issues high on the political agenda and receive attention from the media. Conducting research with these impacts is not without its challenges, however, and completing a high-quality systematic review is often demanding and time-consuming. In this chapter we introduce some of the key considerations for potential review authors who are about to start a systematic review.

1.2 What is the review question?

Getting the research question right is critical for the success of a systematic review. Review authors should ensure that the review addresses an important question to those who are expected to use and act upon its conclusions.

We discuss the formulation of questions in detail in Chapter 2 . For a question about the effects of an intervention, the PICO approach is usually used, which is an acronym for Population, Intervention, Comparison(s) and Outcome. Reviews may have additional questions, for example about how interventions were implemented, economic issues, equity issues or patient experience.

To ensure that the review addresses a relevant question in a way that benefits users, it is important to ensure wide input. In most cases, question formulation should therefore be informed by people with various relevant – but potentially different – perspectives (see Chapter 2, Section 2.4 ).

1.3 Who should do a systematic review?

Systematic reviews should be undertaken by a team. Indeed, Cochrane will not publish a review that is proposed to be undertaken by a single person. Working as a team not only spreads the effort, but ensures that tasks such as the selection of studies for eligibility, data extraction and rating the certainty of the evidence will be performed by at least two people independently, minimizing the likelihood of errors. First-time review authors are encouraged to work with others who are experienced in the process of systematic reviews and to attend relevant training.

Review teams must include expertise in the topic area under review. Topic expertise should not be overly narrow, to ensure that all relevant perspectives are considered. Perspectives from different disciplines can help to avoid assumptions or terminology stemming from an over-reliance on a single discipline. Review teams should also include expertise in systematic review methodology, including statistical expertise.

Arguments have been made that methodological expertise is sufficient to perform a review, and that content expertise should be avoided because of the risk of preconceptions about the effects of interventions (Gøtzsche and Ioannidis 2012). However, it is important that both topic and methodological expertise is present to ensure a good mix of skills, knowledge and objectivity, because topic expertise provides important insight into the implementation of the intervention(s), the nature of the condition being treated or prevented, the relationships between outcomes measured, and other factors that may have an impact on decision making.

A Cochrane Review should represent an independent assessment of the evidence and avoiding financial and non-financial conflicts of interest often requires careful management. It will be important to consider if there are any relevant interests that may constitute a conflict of interest. There are situations where employment, holding of patents and other financial support should prevent people joining an author team. Funding of Cochrane Reviews by commercial organizations with an interest in the outcome of the review is not permitted. To ensure that any issues are identified early in the process, authors planning Cochrane Reviews should consult the Conflict of Interest Policy . Authors should make complete declarations of interest before registration of the review, and refresh these annually thereafter until publication and just prior to publication of the protocol and the review. For authors of review updates, this must be done at the time of the decision to update the review, annually thereafter until publication, and just prior to publication. Authors should also update declarations of interest at any point when their circumstances change.

1.3.1 Involving consumers and other stakeholders

Because the priorities of decision makers and consumers may be different from those of researchers, it is important that review authors consider carefully what questions are important to these different stakeholders. Systematic reviews are more likely to be relevant to a broad range of end users if they are informed by the involvement of people with a range of experiences, in terms of both the topic and the methodology (Thomas et al 2004, Rees and Oliver 2017). Engaging consumers and other stakeholders, such as policy makers, research funders and healthcare professionals, increases relevance, promotes mutual learning, improved uptake and decreases research waste.

Mapping out all potential stakeholders specific to the review question is a helpful first step to considering who might be invited to be involved in a review. Stakeholders typically include: patients and consumers; consumer advocates; policy makers and other public officials; guideline developers; professional organizations; researchers; funders of health services and research; healthcare practitioners, and, on occasion, journalists and other media professionals. Balancing seniority, credibility within the given field, and diversity should be considered. Review authors should also take account of the needs of resource-poor countries and regions in the review process (see Chapter 16 ) and invite appropriate input on the scope of the review and the questions it will address.

It is established good practice to ensure that consumers are involved and engaged in health research, including systematic reviews. Cochrane uses the term ‘consumers’ to refer to a wide range of people, including patients or people with personal experience of a healthcare condition, carers and family members, representatives of patients and carers, service users and members of the public. In 2017, a Statement of Principles for consumer involvement in Cochrane was agreed. This seeks to change the culture of research practice to one where both consumers and other stakeholders are joint partners in research from planning, conduct, and reporting to dissemination. Systematic reviews that have had consumer involvement should be more directly applicable to decision makers than those that have not (see online Chapter II ).

1.3.2 Working with consumers and other stakeholders

Methods for working with consumers and other stakeholders include surveys, workshops, focus groups and involvement in advisory groups. Decisions about what methods to use will typically be based on resource availability, but review teams should be aware of the merits and limitations of such methods. Authors will need to decide who to involve and how to provide adequate support for their involvement. This can include financial reimbursement, the provision of training, and stating clearly expectations of involvement, possibly in the form of terms of reference.

While a small number of consumers or other stakeholders may be part of the review team and become co-authors of the subsequent review, it is sometimes important to bring in a wider range of perspectives and to recognize that not everyone has the capacity or interest in becoming an author. Advisory groups offer a convenient approach to involving consumers and other relevant stakeholders, especially for topics in which opinions differ. Important points to ensure successful involvement include the following.

• The review team should co-ordinate the input of the advisory group to inform key review decisions.
• The advisory group’s input should continue throughout the systematic review process to ensure relevance of the review to end users is maintained.
• Advisory group membership should reflect the breadth of the review question, and consideration should be given to involving vulnerable and marginalized people (Steel 2004) to ensure that conclusions on the value of the interventions are well-informed and applicable to all groups in society (see Chapter 16 ).

Templates such as terms of reference, job descriptions, or person specifications for an advisory group help to ensure clarity about the task(s) required and are available from INVOLVE . The website also gives further information on setting and organizing advisory groups. See also the Cochrane training website for further resources to support consumer involvement.

1.4 The importance of reliability

Systematic reviews aim to be an accurate representation of the current state of knowledge about a given issue. As understanding improves, the review can be updated. Nevertheless, it is important that the review itself is accurate at the time of publication. There are two main reasons for this imperative for accuracy. First, health decisions that affect people’s lives are increasingly taken based on systematic review findings. Current knowledge may be imperfect, but decisions will be better informed when taken in the light of the best of current knowledge. Second, systematic reviews form a critical component of legal and regulatory frameworks; for example, drug licensing or insurance coverage. Here, systematic reviews also need to hold up as auditable processes for legal examination. As systematic reviews need to be both correct, and be seen to be correct, detailed evidence-based methods have been developed to guide review authors as to the most appropriate procedures to follow, and what information to include in their reports to aid auditability.

1.4.1 Expectations for the conduct and reporting of Cochrane Reviews

Cochrane has developed methodological expectations for the conduct, reporting and updating of systematic reviews of interventions (MECIR) and their plain language summaries ( Plain Language Expectations for Authors of Cochrane Summaries ; PLEACS). Developed collaboratively by methodologists and Cochrane editors, they are intended to describe the desirable attributes of a Cochrane Review. The expectations are not all relevant at the same stage of review conduct, so care should be taken to identify those that are relevant at specific points during the review. Different methods should be used at different stages of the review in terms of the planning, conduct, reporting and updating of the review.

Each expectation has a title, a rationale and an elaboration. For the purposes of publication of a review with Cochrane, each has the status of either ‘mandatory’ or ‘highly desirable’. Items described as mandatory are expected to be applied, and if they are not then an appropriate justification should be provided; failure to implement such items may be used as a basis for deciding not to publish a review in the Cochrane Database of Systematic Reviews (CDSR). Items described as highly desirable should generally be implemented, but there are reasonable exceptions and justifications are not required.

All MECIR expectations for the conduct of a review are presented in the relevant chapters of this Handbook . Expectations for reporting of completed reviews (including PLEACS) are described in online Chapter III . The recommendations provided in the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) Statement have been incorporated into the Cochrane reporting expectations, ensuring compliance with the PRISMA recommendations and summarizing attributes of reporting that should allow a full assessment of the methods and findings of the review (Moher et al 2009).

1.5 Protocol development

Preparing a systematic review is complex and involves many judgements. To minimize the potential for bias in the review process, these judgements should be made as far as possible in ways that do not depend on the findings of the studies included in the review. Review authors’ prior knowledge of the evidence may, for example, influence the definition of a systematic review question, the choice of criteria for study eligibility, or the pre-specification of intervention comparisons and outcomes to analyse. It is important that the methods to be used should be established and documented in advance (see MECIR Box 1.5.a , MECIR Box 1.5.b and MECIR Box 1.5.c ).

Publication of a protocol for a review that is written without knowledge of the available studies reduces the impact of review authors’ biases, promotes transparency of methods and processes, reduces the potential for duplication, allows peer review of the planned methods before they have been completed, and offers an opportunity for the review team to plan resources and logistics for undertaking the review itself. All chapters in the Handbook should be consulted when drafting the protocol. Since systematic reviews are by their nature retrospective, an element of knowledge of the evidence is often inevitable. This is one reason why non-content experts such as methodologists should be part of the review team (see Section 1.3 ). Two exceptions to the retrospective nature of a systematic review are a meta-analysis of a prospectively planned series of trials and some living systematic reviews, as described in Chapter 22 .

The review question should determine the methods used in the review, and not vice versa. The question may concern a relatively straightforward comparison of one treatment with another; or it may necessitate plans to compare different treatments as part of a network meta-analysis, or assess differential effects of an intervention in different populations or delivered in different ways.

The protocol sets out the context in which the review is being conducted. It presents an opportunity to develop ideas that are foundational for the review. This concerns, most explicitly, definition of the eligibility criteria such as the study participants and the choice of comparators and outcomes. The eligibility criteria may also be defined following the development of a logic model (or an articulation of the aspects of an extent logic model that the review is addressing) to explain how the intervention might work (see Chapter 2, Section 2.5.1 ).

MECIR Box 1.5.a Relevant expectations for conduct of intervention reviews

A key purpose of the protocol is to make plans to minimize bias in the eventual findings of the review. Reliable synthesis of available evidence requires a planned, systematic approach. Threats to the validity of systematic reviews can come from the studies they include or the process by which reviews are conducted. Biases within the studies can arise from the method by which participants are allocated to the intervention groups, awareness of intervention group assignment, and the collection, analysis and reporting of data. Methods for examining these issues should be specified in the protocol. Review processes can generate bias through a failure to identify an unbiased (and preferably complete) set of studies, and poor quality assurance throughout the review. The availability of research may be influenced by the nature of the results (i.e. reporting bias). To reduce the impact of this form of bias, searching may need to include unpublished sources of evidence (Dwan et al 2013) ( MECIR Box 1.5.b ).

MECIR Box 1.5.b Relevant expectations for the conduct of intervention reviews

Developing a protocol for a systematic review has benefits beyond reducing bias. Investing effort in designing a systematic review will make the process more manageable and help to inform key priorities for the review. Defining the question, referring to it throughout, and using appropriate methods to address the question focuses the analysis and reporting, ensuring the review is most likely to inform treatment decisions for funders, policy makers, healthcare professionals and consumers. Details of the planned analyses, including investigations of variability across studies, should be specified in the protocol, along with methods for interpreting the results through the systematic consideration of factors that affect confidence in estimates of intervention effect ( MECIR Box 1.5.c ).

MECIR Box 1.5.c Relevant expectations for conduct of intervention reviews

While the intention should be that a review will adhere to the published protocol, changes in a review protocol are sometimes necessary. This is also the case for a protocol for a randomized trial, which must sometimes be changed to adapt to unanticipated circumstances such as problems with participant recruitment, data collection or event rates. While every effort should be made to adhere to a predetermined protocol, this is not always possible or appropriate. It is important, however, that changes in the protocol should not be made based on how they affect the outcome of the research study, whether it is a randomized trial or a systematic review. Post hoc decisions made when the impact on the results of the research is known, such as excluding selected studies from a systematic review, or changing the statistical analysis, are highly susceptible to bias and should therefore be avoided unless there are reasonable grounds for doing this.

Enabling access to a protocol through publication (all Cochrane Protocols are published in the CDSR ) and registration on the PROSPERO register of systematic reviews reduces duplication of effort, research waste, and promotes accountability. Changes to the methods outlined in the protocol should be transparently declared.

This Handbook provides details of the systematic review methods developed or selected by Cochrane. They are intended to address the need for rigour, comprehensiveness and transparency in preparing a Cochrane systematic review. All relevant chapters – including those describing procedures to be followed in the later stages of the review – should be consulted during the preparation of the protocol. A more specific description of the structure of Cochrane Protocols is provide in online Chapter II .

1.6 Data management and quality assurance

Systematic reviews should be replicable, and retaining a record of the inclusion decisions, data collection, transformations or adjustment of data will help to establish a secure and retrievable audit trail. They can be operationally complex projects, often involving large research teams operating in different sites across the world. Good data management processes are essential to ensure that data are not inadvertently lost, facilitating the identification and correction of errors and supporting future efforts to update and maintain the review. Transparent reporting of review decisions enables readers to assess the reliability of the review for themselves.

Review management software, such as Covidence and EPPI-Reviewer , can be used to assist data management and maintain consistent and standardized records of decisions made throughout the review. These tools offer a central repository for review data that can be accessed remotely throughout the world by members of the review team. They record independent assessment of studies for inclusion, risk of bias and extraction of data, enabling checks to be made later in the process if needed. Research has shown that even experienced reviewers make mistakes and disagree with one another on risk-of-bias assessments, so it is particularly important to maintain quality assurance here, despite its cost in terms of author time. As more sophisticated information technology tools begin to be deployed in reviews (see Chapter 4, Section 4.6.6.2 and Chapter 22, Section 22.2.4 ), it is increasingly apparent that all review data – including the initial decisions about study eligibility – have value beyond the scope of the individual review. For example, review updates can be made more efficient through (semi-) automation when data from the original review are available for machine learning.

1.7 Chapter information

Authors: Toby J Lasserson, James Thomas, Julian PT Higgins

Acknowledgements: This chapter builds on earlier versions of the Handbook . We would like to thank Ruth Foxlee, Richard Morley, Soumyadeep Bhaumik, Mona Nasser, Dan Fox and Sally Crowe for their contributions to Section 1.3 .

Funding: JT is supported by the National Institute for Health Research (NIHR) Collaboration for Leadership in Applied Health Research and Care North Thames at Barts Health NHS Trust. JPTH is a member of the NIHR Biomedical Research Centre at University Hospitals Bristol NHS Foundation Trust and the University of Bristol. JPTH received funding from National Institute for Health Research Senior Investigator award NF-SI-0617-10145. The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health.

1.8 References

Antman E, Lau J, Kupelnick B, Mosteller F, Chalmers T. A comparison of results of meta-analyses of randomized control trials and recommendations of clinical experts: treatment for myocardial infarction. JAMA 1992; 268 : 240–248.

Chalmers I, Bracken MB, Djulbegovic B, Garattini S, Grant J, Gulmezoglu AM, Howells DW, Ioannidis JP, Oliver S. How to increase value and reduce waste when research priorities are set. Lancet 2014; 383 : 156–165.

Chandler J, Hopewell S. Cochrane methods – twenty years experience in developing systematic review methods. Systematic Reviews 2013; 2 : 76.

Dwan K, Gamble C, Williamson PR, Kirkham JJ, Reporting Bias Group. Systematic review of the empirical evidence of study publication bias and outcome reporting bias: an updated review. PloS One 2013; 8 : e66844.

Gøtzsche PC, Ioannidis JPA. Content area experts as authors: helpful or harmful for systematic reviews and meta-analyses? BMJ 2012; 345 .

Macleod MR, Michie S, Roberts I, Dirnagl U, Chalmers I, Ioannidis JP, Al-Shahi Salman R, Chan AW, Glasziou P. Biomedical research: increasing value, reducing waste. Lancet 2014; 383 : 101–104.

Moher D, Liberati A, Tetzlaff J, Altman D, PRISMA Group. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. PLoS Medicine 2009; 6 : e1000097.

Oxman A, Guyatt G. The science of reviewing research. Annals of the New York Academy of Sciences 1993; 703 : 125–133.

Rees R, Oliver S. Stakeholder perspectives and participation in reviews. In: Gough D, Oliver S, Thomas J, editors. An Introduction to Systematic Reviews . 2nd ed. London: Sage; 2017. p. 17–34.

Steel R. Involving marginalised and vulnerable people in research: a consultation document (2nd revision). INVOLVE; 2004.

Thomas J, Harden A, Oakley A, Oliver S, Sutcliffe K, Rees R, Brunton G, Kavanagh J. Integrating qualitative research with trials in systematic reviews. BMJ 2004; 328 : 1010–1012.

For permission to re-use material from the Handbook (either academic or commercial), please see here for full details.

Systematic Reviews and Meta Analysis

• Getting Started
• Guides and Standards
• Review Protocols
• Databases and Sources
• Randomized Controlled Trials
• Controlled Clinical Trials
• Observational Designs
• Tests of Diagnostic Accuracy
• Software and Tools
• Where do I get all those articles?
• Collaborations
• EPI 233/528
• Countway Mediated Search
• Risk of Bias (RoB)

Systematic review Q & A

What is a systematic review.

A systematic review is guided filtering and synthesis of all available evidence addressing a specific, focused research question, generally about a specific intervention or exposure. The use of standardized, systematic methods and pre-selected eligibility criteria reduce the risk of bias in identifying, selecting and analyzing relevant studies. A well-designed systematic review includes clear objectives, pre-selected criteria for identifying eligible studies, an explicit methodology, a thorough and reproducible search of the literature, an assessment of the validity or risk of bias of each included study, and a systematic synthesis, analysis and presentation of the findings of the included studies. A systematic review may include a meta-analysis.

For details about carrying out systematic reviews, see the Guides and Standards section of this guide.

Is my research topic appropriate for systematic review methods?

A systematic review is best deployed to test a specific hypothesis about a healthcare or public health intervention or exposure. By focusing on a single intervention or a few specific interventions for a particular condition, the investigator can ensure a manageable results set. Moreover, examining a single or small set of related interventions, exposures, or outcomes, will simplify the assessment of studies and the synthesis of the findings.

Systematic reviews are poor tools for hypothesis generation: for instance, to determine what interventions have been used to increase the awareness and acceptability of a vaccine or to investigate the ways that predictive analytics have been used in health care management. In the first case, we don't know what interventions to search for and so have to screen all the articles about awareness and acceptability. In the second, there is no agreed on set of methods that make up predictive analytics, and health care management is far too broad. The search will necessarily be incomplete, vague and very large all at the same time. In most cases, reviews without clearly and exactly specified populations, interventions, exposures, and outcomes will produce results sets that quickly outstrip the resources of a small team and offer no consistent way to assess and synthesize findings from the studies that are identified.

If not a systematic review, then what?

You might consider performing a scoping review . This framework allows iterative searching over a reduced number of data sources and no requirement to assess individual studies for risk of bias. The framework includes built-in mechanisms to adjust the analysis as the work progresses and more is learned about the topic. A scoping review won't help you limit the number of records you'll need to screen (broad questions lead to large results sets) but may give you means of dealing with a large set of results.

This tool can help you decide what kind of review is right for your question.

Can my student complete a systematic review during her summer project?

Probably not. Systematic reviews are a lot of work. Including creating the protocol, building and running a quality search, collecting all the papers, evaluating the studies that meet the inclusion criteria and extracting and analyzing the summary data, a well done review can require dozens to hundreds of hours of work that can span several months. Moreover, a systematic review requires subject expertise, statistical support and a librarian to help design and run the search. Be aware that librarians sometimes have queues for their search time. It may take several weeks to complete and run a search. Moreover, all guidelines for carrying out systematic reviews recommend that at least two subject experts screen the studies identified in the search. The first round of screening can consume 1 hour per screener for every 100-200 records. A systematic review is a labor-intensive team effort.

How can I know if my topic has been been reviewed already?

Before starting out on a systematic review, check to see if someone has done it already. In PubMed you can use the systematic review subset to limit to a broad group of papers that is enriched for systematic reviews. You can invoke the subset by selecting if from the Article Types filters to the left of your PubMed results, or you can append AND systematic[sb] to your search. For example:

"neoadjuvant chemotherapy" AND systematic[sb]

The systematic review subset is very noisy, however. To quickly focus on systematic reviews (knowing that you may be missing some), simply search for the word systematic in the title:

"neoadjuvant chemotherapy" AND systematic[ti]

Any PRISMA-compliant systematic review will be captured by this method since including the words "systematic review" in the title is a requirement of the PRISMA checklist. Cochrane systematic reviews do not include 'systematic' in the title, however. It's worth checking the Cochrane Database of Systematic Reviews independently.

You can also search for protocols that will indicate that another group has set out on a similar project. Many investigators will register their protocols in PROSPERO , a registry of review protocols. Other published protocols as well as Cochrane Review protocols appear in the Cochrane Methodology Register, a part of the Cochrane Library .

• Next: Guides and Standards >>
• Last Updated: Feb 26, 2024 3:17 PM
• URL: https://guides.library.harvard.edu/meta-analysis

Library Services

UCL LIBRARY SERVICES

• Guides and databases
• Library skills
• Systematic reviews

What are systematic reviews?

• Types of systematic reviews
• Formulating a research question
• Identifying studies
• Searching databases
• Describing and appraising studies
• Synthesis and systematic maps
• Software for systematic reviews
• Online training and support
• Live and face to face training
• Individual support
• Further help

Systematic reviews are a type of literature review of research which require equivalent standards of rigour as primary research. They have a clear, logical rationale that is reported to the reader of the review. They are used in research and policymaking to inform evidence-based decisions and practice. They differ from traditional literature reviews particularly in the following elements of conduct and reporting.

Systematic reviews: 

• use explicit and transparent methods
• are a piece of research following a standard set of stages
• are accountable, replicable and updateable
• involve users to ensure a review is relevant and useful.

For example, systematic reviews (like all research) should have a clear research question, and the perspective of the authors in their approach to addressing the question is described. There are clearly described methods on how each study in a review was identified, how that study was appraised for quality and relevance and how it is combined with other studies in order to address the review question. A systematic review usually involves more than one person in order to increase the objectivity and trustworthiness of the reviews methods and findings.

Research protocols for systematic reviews may be peer-reviewed and published or registered in a suitable repository to help avoid duplication of reviews and for comparisons to be made with the final review and the planned review.

• History of systematic reviews to inform policy (EPPI-Centre)
• Six reasons why it is important to be systematic (EPPI-Centre)
• Evidence Synthesis International (ESI): Position Statement Describes the issues, principles and goals in synthesising research evidence to inform policy, practice and decisions

On this page

Should all literature reviews be 'systematic reviews', different methods for systematic reviews, reporting standards for systematic reviews.

Literature reviews provide a more complete picture of research knowledge than is possible from individual pieces of research. This can be used to: clarify what is known from research, provide new perspectives, build theory, test theory, identify research gaps or inform research agendas.

A systematic review requires a considerable amount of time and resources, and is one type of literature review.

If the purpose of a review is to make justifiable evidence claims, then it should be systematic, as a systematic review uses rigorous explicit methods. The methods used can depend on the purpose of the review, and the time and resources available.

A 'non-systematic review' might use some of the same methods as systematic reviews, such as systematic approaches to identify studies or quality appraise the literature. There may be times when this approach can be useful. In a student dissertation, for example, there may not be the time to be fully systematic in a review of the literature if this is only one small part of the thesis. In other types of research, there may also be a need to obtain a quick and not necessarily thorough overview of a literature to inform some other work (including a systematic review). Another example, is where policymakers, or other people using research findings, want to make quick decisions and there is no systematic review available to help them. They have a choice of gaining a rapid overview of the research literature or not having any research evidence to help their decision-making. 

Just like any other piece of research, the methods used to undertake any literature review should be carefully planned to justify the conclusions made. 

Finding out about different types of systematic reviews and the methods used for systematic reviews, and reading both systematic and other types of review will help to understand some of the differences. 

Typically, a systematic review addresses a focussed, structured research question in order to inform understanding and decisions on an area. (see the  Formulating a research question  section for examples). 

Sometimes systematic reviews ask a broad research question, and one strategy to achieve this is the use of several focussed sub-questions each addressed by sub-components of the review.  

Another strategy is to develop a map to describe the type of research that has been undertaken in relation to a research question. Some maps even describe over 2,000 papers, while others are much smaller. One purpose of a map is to help choose a sub-set of studies to explore more fully in a synthesis. There are also other purposes of maps: see the box on  systematic evidence maps  for further information. 

Reporting standards specify minimum elements that need to go into the reporting of a review. The reporting standards refer mainly to methodological issues but they are not as detailed or specific as critical appraisal for the methodological standards of conduct of a review.

A number of organisations have developed specific guidelines and standards for both the conducting and reporting on systematic reviews in different topic areas.  

• PRISMA PRISMA is a reporting standard and is an acronym for Preferred Reporting Items for Systematic Reviews and Meta-Analyses. The Key Documents section of the PRISMA website links to a checklist, flow diagram and explanatory notes. PRISMA is less useful for certain types of reviews, including those that are iterative.
• eMERGe eMERGe is a reporting standard that has been developed for meta-ethnographies, a qualitative synthesis method.
• ROSES: RepOrting standards for Systematic Evidence Syntheses Reporting standards, including forms and flow diagram, designed specifically for systematic reviews and maps in the field of conservation and environmental management.

Useful books about systematic reviews

Systematic approaches to a successful literature review

An introduction to systematic reviews

Cochrane handbook for systematic reviews of interventions

Systematic reviews: crd's guidance for undertaking reviews in health care.

Finding what works in health care: Standards for systematic reviews

Systematic Reviews in the Social Sciences

Meta-analysis and research synthesis.

Research Synthesis and Meta-Analysis

Doing a Systematic Review

Literature reviews.

• What is a literature review?
• Why are literature reviews important?
• << Previous: Systematic reviews
• Next: Types of systematic reviews >>
• Last Updated: Apr 4, 2024 10:09 AM
• URL: https://library-guides.ucl.ac.uk/systematic-reviews

University Libraries      University of Nevada, Reno

• Skill Guides
• Subject Guides

Systematic, Scoping, and Other Literature Reviews: Overview

• Project Planning

What Is a Systematic Review?

Regular literature reviews are simply summaries of the literature on a particular topic. A systematic review, however, is a comprehensive literature review conducted to answer a specific research question. Authors of a systematic review aim to find, code, appraise, and synthesize all of the previous research on their question in an unbiased and well-documented manner. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) outline the minimum amount of information that needs to be reported at the conclusion of a systematic review project. 

Other types of what are known as "evidence syntheses," such as scoping, rapid, and integrative reviews, have varying methodologies. While systematic reviews originated with and continue to be a popular publication type in medicine and other health sciences fields, more and more researchers in other disciplines are choosing to conduct evidence syntheses. 

This guide will walk you through the major steps of a systematic review and point you to key resources including Covidence, a systematic review project management tool. For help with systematic reviews and other major literature review projects, please send us an email at  [email protected] .

Getting Help with Reviews

Organization such as the Institute of Medicine recommend that you consult a librarian when conducting a systematic review. Librarians at the University of Nevada, Reno can help you:

• Understand best practices for conducting systematic reviews and other evidence syntheses in your discipline
• Choose and formulate a research question
• Decide which review type (e.g., systematic, scoping, rapid, etc.) is the best fit for your project
• Determine what to include and where to register a systematic review protocol
• Select search terms and develop a search strategy
• Identify databases and platforms to search
• Find the full text of articles and other sources
• Become familiar with free citation management (e.g., EndNote, Zotero)
• Get access to you and help using Covidence, a systematic review project management tool

Doing a Systematic Review

• Plan - This is the project planning stage. You and your team will need to develop a good research question, determine the type of review you will conduct (systematic, scoping, rapid, etc.), and establish the inclusion and exclusion criteria (e.g., you're only going to look at studies that use a certain methodology). All of this information needs to be included in your protocol. You'll also need to ensure that the project is viable - has someone already done a systematic review on this topic? Do some searches and check the various protocol registries to find out. 
• Identify - Next, a comprehensive search of the literature is undertaken to ensure all studies that meet the predetermined criteria are identified. Each research question is different, so the number and types of databases you'll search - as well as other online publication venues - will vary. Some standards and guidelines specify that certain databases (e.g., MEDLINE, EMBASE) should be searched regardless. Your subject librarian can help you select appropriate databases to search and develop search strings for each of those databases.  
• Evaluate - In this step, retrieved articles are screened and sorted using the predetermined inclusion and exclusion criteria. The risk of bias for each included study is also assessed around this time. It's best if you import search results into a citation management tool (see below) to clean up the citations and remove any duplicates. You can then use a tool like Rayyan (see below) to screen the results. You should begin by screening titles and abstracts only, and then you'll examine the full text of any remaining articles. Each study should be reviewed by a minimum of two people on the project team. 
• Collect - Each included study is coded and the quantitative or qualitative data contained in these studies is then synthesized. You'll have to either find or develop a coding strategy or form that meets your needs. 
• Explain - The synthesized results are articulated and contextualized. What do the results mean? How have they answered your research question?
• Summarize - The final report provides a complete description of the methods and results in a clear, transparent fashion. 

Adapted from

Types of reviews, systematic review.

These types of studies employ a systematic method to analyze and synthesize the results of numerous studies. "Systematic" in this case means following a strict set of steps - as outlined by entities like PRISMA and the Institute of Medicine - so as to make the review more reproducible and less biased. Consistent, thorough documentation is also key. Reviews of this type are not meant to be conducted by an individual but rather a (small) team of researchers. Systematic reviews are widely used in the health sciences, often to find a generalized conclusion from multiple evidence-based studies. 

Meta-Analysis

A systematic method that uses statistics to analyze the data from numerous studies. The researchers combine the data from studies with similar data types and analyze them as a single, expanded dataset. Meta-analyses are a type of systematic review.

Scoping Review

A scoping review employs the systematic review methodology to explore a broader topic or question rather than a specific and answerable one, as is generally the case with a systematic review. Authors of these types of reviews seek to collect and categorize the existing literature so as to identify any gaps.

Rapid Review

Rapid reviews are systematic reviews conducted under a time constraint. Researchers make use of workarounds to complete the review quickly (e.g., only looking at English-language publications), which can lead to a less thorough and more biased review. 

Narrative Review

A traditional literature review that summarizes and synthesizes the findings of numerous original research articles. The purpose and scope of narrative literature reviews vary widely and do not follow a set protocol. Most literature reviews are narrative reviews. 

Umbrella Review

Umbrella reviews are, essentially, systematic reviews of systematic reviews. These compile evidence from multiple review studies into one usable document. 

Grant, Maria J., and Andrew Booth. “A Typology of Reviews: An Analysis of 14 Review Types and Associated Methodologies.” Health Information & Libraries Journal , vol. 26, no. 2, 2009, pp. 91-108. doi: 10.1111/j.1471-1842.2009.00848.x .

• Next: Project Planning >>

What is a Systematic Literature Review?

A systematic literature review (SLR) is an independent academic method that aims to identify and evaluate all relevant literature on a topic in order to derive conclusions about the question under consideration. "Systematic reviews are undertaken to clarify the state of existing research and the implications that should be drawn from this." (Feak & Swales, 2009, p. 3) An SLR can demonstrate the current state of research on a topic, while identifying gaps and areas requiring further research with regard to a given research question. A formal methodological approach is pursued in order to reduce distortions caused by an overly restrictive selection of the available literature and to increase the reliability of the literature selected (Tranfield, Denyer & Smart, 2003). A special aspect in this regard is the fact that a research objective is defined for the search itself and the criteria for determining what is to be included and excluded are defined prior to conducting the search. The search is mainly performed in electronic literature databases (such as Business Source Complete or Web of Science), but also includes manual searches (reviews of reference lists in relevant sources) and the identification of literature not yet published in order to obtain a comprehensive overview of a research topic.

An SLR protocol documents all the information gathered and the steps taken as part of an SLR in order to make the selection process transparent and reproducible. The PRISMA flow-diagram support you in making the selection process visible.

In an ideal scenario, experts from the respective research discipline, as well as experts working in the relevant field and in libraries, should be involved in setting the search terms . As a rule, the literature is selected by two or more reviewers working independently of one another. Both measures serve the purpose of increasing the objectivity of the literature selection. An SLR must, then, be more than merely a summary of a topic (Briner & Denyer, 2012). As such, it also distinguishes itself from “ordinary” surveys of the available literature. The following table shows the differences between an SLR and an “ordinary” literature review.

• Charts of BSWL workshop (pdf, 2.88 MB)
• Listen to the interview (mp4, 12.35 MB)

Differences to "common" literature reviews

What are the objectives of slrs.

• Avoidance of research redundancies despite a growing amount of publications
• Identification of research areas, gaps and methods
• Input for evidence-based management, which allows to base management decisions on scientific methods and findings
• Identification of links between different areas of researc

Process steps of an SLR

A SLR has several process steps which are defined differently in the literature (Fink 2014, p. 4; Guba 2008, Transfield et al. 2003). We distinguish the following steps which are adapted to the economics and management research area:

1. Defining research questions

Briner & Denyer (2009, p. 347ff.) have developed the CIMO scheme to establish clearly formulated and answerable research questions in the field of economic sciences:

C – CONTEXT:  Which individuals, relationships, institutional frameworks and systems are being investigated?

I – Intervention:  The effects of which event, action or activity are being investigated?

M – Mechanisms:  Which mechanisms can explain the relationship between interventions and results? Under what conditions do these mechanisms take effect?

O – Outcomes:  What are the effects of the intervention? How are the results measured? What are intended and unintended effects?

The objective of the systematic literature review is used to formulate research questions such as “How can a project team be led effectively?”. Since there are numerous interpretations and constructs for “effective”, “leadership” and “project team”, these terms must be particularized.

With the aid of the scheme, the following concrete research questions can be derived with regard to this example:

Under what conditions (C) does leadership style (I) influence the performance of project teams (O)?

Which constructs have an effect upon the influence of leadership style (I) on a project team’s performance (O)?          

Research questions do not necessarily need to follow the CIMO scheme, but they should:

• ... be formulated in a clear, focused and comprehensible manner and be answerable;
• ... have been determined prior to carrying out the SLR;
• ... consist of general and specific questions.

As early as this stage, the criteria for inclusion and exclusion are also defined. The selection of the criteria must be well-grounded. This may include conceptual factors such as a geographical or temporal restrictions, congruent definitions of constructs, as well as quality criteria (journal impact factor > x).

2. Selecting databases and other research sources

The selection of sources must be described and explained in detail. The aim is to find a balance between the relevance of the sources (content-related fit) and the scope of the sources.

In the field of economic sciences, there are a number of literature databases that can be searched as part of an SLR. Some examples in this regard are:

• Business Source Complete
• ProQuest One Business
• Web of Science
• EconBiz        

Our video " Selecting the right databases " explains how to find relevant databases for your topic.

Literature databases are an important source of research for SLRs, as they can minimize distortions caused by an individual literature selection (selection bias), while offering advantages for a systematic search due to their data structure. The aim is to find all database entries on a topic and thus keep the retrieval bias low (tutorial on retrieval bias ).  Besides articles from scientific journals, it is important to inlcude working papers, conference proceedings, etc to reduce the publication bias ( tutorial on publication bias ).

Our online self-study course " Searching economic databases " explains step 2 und 3.

3. Defining search terms

Once the literature databases and other research sources have been selected, search terms are defined. For this purpose, the research topic/questions is/are divided into blocks of terms of equal ranking. This approach is called the block-building method (Guba 2008, p. 63). The so-called document-term matrix, which lists topic blocks and search terms according to a scheme, is helpful in this regard. The aim is to identify as many different synonyms as possible for the partial terms. A precisely formulated research question facilitates the identification of relevant search terms. In addition, keywords from particularly relevant articles support the formulation of search terms.

A document-term matrix for the topic “The influence of management style on the performance of project teams” is shown in this example .

Identification of headwords and keywords

When setting search terms, a distinction must be made between subject headings and keywords, both of which are described below:

• appear in the title, abstract and/or text
• sometimes specified by the author, but in most cases automatically generated
• non-standardized
• different spellings and forms (singular/plural) must be searched separately

Subject headings

• describe the content
• are generated by an editorial team
• are listed in a standardized list (thesaurus)
• may comprise various keywords
• include different spellings
• database-specific

Subject headings are a standardized list of words that are generated by the specialists in charge of some databases. This so-called index of subject headings (thesaurus) helps searchers find relevant articles, since the headwords indicate the content of a publication. By contrast, an ordinary keyword search does not necessarily result in a content-related fit, since the database also displays articles in which, for example, a word appears once in the abstract, even though the article’s content does not cover the topic.

Nevertheless, searches using both headwords and keywords should be conducted, since some articles may not yet have been assigned headwords, or errors may have occurred during the assignment of headwords. 

To add headwords to your search in the Business Source Complete database, please select the Thesaurus tab at the top. Here you can find headwords in a new search field and integrate them into your search query. In the search history, headwords are marked with the addition DE (descriptor).

The EconBiz database of the German National Library of Economics (ZBW – Leibniz Information Centre for Economics), which also contains German-language literature, has created its own index of subject headings with the STW Thesaurus for Economics . Headwords are integrated into the search by being used in the search query.

Since the indexes of subject headings divide terms into synonyms, generic terms and sub-aspects, they facilitate the creation of a document-term matrix. For this purpose it is advisable to specify in the document-term matrix the origin of the search terms (STW Thesaurus for Economics, Business Source Complete, etc.).

Searching in literature databases

Once the document-term matrix has been defined, the search in literature databases begins. It is recommended to enter each word of the document-term matrix individually into the database in order to obtain a good overview of the number of hits per word. Finally, all the words contained in a block of terms are linked with the Boolean operator OR and thereby a union of all the words is formed. The latter are then linked with each other using the Boolean operator AND. In doing so, each block should be added individually in order to see to what degree the number of hits decreases.

Since the search query must be set up separately for each database, tools such as  LitSonar  have been developed to enable a systematic search across different databases. LitSonar was created by  Professor Dr. Ali Sunyaev (Institute of Applied Informatics and Formal Description Methods – AIFB) at the Karlsruhe Institute of Technology.

Advanced search

Certain database-specific commands can be used to refine a search, for example, by taking variable word endings into account (*) or specifying the distance between two words, etc. Our overview shows the most important search commands for our top databases.

Additional searches in sources other than literature databases

In addition to literature databases, other sources should also be searched. Fink (2014, p. 27) lists the following reasons for this:

• the topic is new and not yet included in indexes of subject headings;
• search terms are not used congruently in articles because uniform definitions do not exist;
• some studies are still in the process of being published, or have been completed, but not published.

Therefore, further search strategies are manual search, bibliographic analysis, personal contacts and academic networks (Briner & Denyer, p. 349). Manual search means that you go through the source information of relevant articles and supplement your hit list accordingly. In addition, you should conduct a targeted search for so-called gray literature, that is, literature not distributed via the book trade, such as working papers from specialist areas and conference reports. By including different types of publications, the so-called publication bias (DBWM video “Understanding publication bias” ) – that is, distortions due to exclusive use of articles from peer-reviewed journals – should be kept to a minimum.

The PRESS-Checklist can support you to check the correctness of your search terms.

4. Merging hits from different databases

In principle, large amounts of data can be easily collected, structured and sorted with data processing programs such as Excel. Another option is to use literature management programs such as EndNote, Citavi or Zotero. The Saxon State and University Library Dresden (SLUB Dresden) provides an  overview of current literature management programs  . Software for qualitative data analysis such as NVivo is equally suited for data processing. A comprehensive overview of the features of different tools that support the SLR process can be found in Bandara et al. (2015).

Our online-self study course "Managing literature with Citavi" shows you how to use the reference management software Citavi.

When conducting an SLR, you should specify for each hit the database from which it originates and the date on which the query was made. In addition, you should always indicate how many hits you have identified in the various databases or, for example, by manual search.

Exporting data from literature databases

Exporting from literature databases is very easy. In  Business Source Complete  , you must first click on the “Share” button in the hit list, then “Email a link to download exported results” at the very bottom and then select the appropriate format for the respective literature program.

In the  Web of Science  database, you must select “Export” and select the relevant format. Tip: You can adjust the extracted data fields. Since for example the abstract is not automatically exported, decide which data fields are of interest for you.

Exporting data from the literature database  EconBiz  is somewhat more complex. Here you must first create a marked list and then select each hit individually and add it to the marked list. Afterwards, articles on the list can be exported.

After merging all hits from the various databases, duplicate entries (duplicates) are deleted.

5. Applying inclusion and exclusion criteria

All publications are evaluated in the literature management program applying the previously defined criteria for inclusion and exclusion. Only those sources that survive this selection process will subsequently be analyzed. The review process and inclusion criteria should be tested with a small sample and adjustments made if necessary before applying it to all articles. In the ideal case, even this selection would be carried out by more than one person, with each working independently of one another. It needs to be made clear how discrepancies between reviewers are dealt with. 

The review of the criteria for inclusion and exclusion is primarily based on the title, abstract and subject headings in the databases, as well as on the keywords provided by the authors of a publication in the first step. In a second step the whole article / source will be read.

Within the Citavi literature-management program, you can supplement title data by adding your own fields. In this regard, the criteria for inclusion can be listed individually and marked with 0 in the free text field for being “not fulfilled” and with 1 for being “fulfilled”. In the table view of all titles, you can use the column function to select which columns should be displayed. Here you can include the criteria for inclusion. By exporting the title list to Excel, it is easy to calculate how many titles remain when applying the criteria for inclusion and exclusion.

In addition to the common literature management tools, you can also use software tools that have been developed to support SLRs. The central library of the university in Zurich has published an overview and evaluation of different tools based on a survey among researchers. --> View SLR tools

The selection process needs to be made transparent. The PRISMA flow diagram supports the visualization of the number of included / excluded studies.

Forward and backward search

Should it become apparent that the number of sources found is relatively small, or if you wish to proceed with particular thoroughness, a forward-and-backward search based on the sources found is recommendable (Webster & Watson 2002, p. xvi). A backward search means going through the bibliographies of the sources found. A forward search, by contrast, identifies articles that have cited the relevant publications. The Web of Science and Scopus databases can be used to perform citation analyses.

6. Perform the review

As the next step, the remaining titles are analyzed as to their content by reading them several times in full. Information is extracted according to defined criteria and the quality of the publications is evaluated. If the data extraction is carried out by more than one person, a training ensures that there will be no differences between the reviewers.

Depending on the research questions there exist diffent methods for data abstraction (content analysis, concept matrix etc.). A so-called concept matrix can be used to structure the content of information (Webster & Watson 2002, p. xvii). The image to the right gives an example of a concept matrix according to Becker (2014).

Particularly in the field of economic sciences, the evaluation of a study’s quality cannot be performed according to a generally valid scheme, such as those existing in the field of medicine, for instance. Quality assessment therefore depends largely on the research questions.

Based on the findings of individual studies, a meta-level is then applied to try to understand what similarities and differences exist between the publications, what research gaps exist, etc. This may also result in the development of a theoretical model or reference framework.

Example concept matrix (Becker 2013) on the topic Business Process Management

7. synthesizing results.

Once the review has been conducted, the results must be compiled and, on the basis of these, conclusions derived with regard to the research question (Fink 2014, p. 199ff.). This includes, for example, the following aspects:

• historical development of topics (histogram, time series: when, and how frequently, did publications on the research topic appear?);
• overview of journals, authors or specialist disciplines dealing with the topic;
• comparison of applied statistical methods;
• topics covered by research;
• identifying research gaps;
• developing a reference framework;
• developing constructs;
• performing a meta-analysis: comparison of the correlations of the results of different empirical studies (see for example Fink 2014, p. 203 on conducting meta-analyses)

Publications about the method

Bandara, W., Furtmueller, E., Miskon, S., Gorbacheva, E., & Beekhuyzen, J. (2015). Achieving Rigor in Literature Reviews: Insights from Qualitative Data Analysis and Tool-Support.  Communications of the Association for Information Systems . 34(8), 154-204.

Booth, A., Papaioannou, D., and Sutton, A. (2012)  Systematic approaches to a successful literature review.  London: Sage.

Briner, R. B., & Denyer, D. (2012). Systematic Review and Evidence Synthesis as a Practice and Scholarship Tool. In Rousseau, D. M. (Hrsg.),  The Oxford Handbook of Evidenence Based Management . (S. 112-129). Oxford: Oxford University Press.

Durach, C. F., Wieland, A., & Machuca, Jose A. D. (2015). Antecedents and dimensions of supply chain robustness: a systematic literature review . International Journal of Physical Distribution & Logistic Management , 46 (1/2), 118-137. doi:  https://doi.org/10.1108/IJPDLM-05-2013-0133

Feak, C. B., & Swales, J. M. (2009). Telling a Research Story: Writing a Literature Review.  English in Today's Research World 2.  Ann Arbor: University of Michigan Press. doi:  10.3998/mpub.309338

Fink, A. (2014).  Conducting Research Literature Reviews: From the Internet to Paper  (4. Aufl.). Los Angeles, London, New Delhi, Singapore, Washington DC: Sage Publication.

Fisch, C., & Block, J. (2018). Six tips for your (systematic) literature review in business and management research.  Management Review Quarterly,  68, 103–106 (2018).  doi.org/10.1007/s11301-018-0142-x

Guba, B. (2008). Systematische Literaturrecherche.  Wiener Medizinische Wochenschrift , 158 (1-2), S. 62-69. doi:  doi.org/10.1007/s10354-007-0500-0  Hart, C.  Doing a literature review: releasing the social science research imagination.  London: Sage.

Jesson, J. K., Metheson, L. & Lacey, F. (2011).  Doing your Literature Review - traditional and Systematic Techniques . Los Angeles, London, New Delhi, Singapore, Washington DC: Sage Publication.

Page MJ, McKenzie JE, Bossuyt PM, Boutron I, Hoffmann TC, Mulrow CD, et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ 2021;372:n71. doi: 10.1136/bmj.n71.

Petticrew, M. and Roberts, H. (2006).  Systematic Reviews in the Social Sciences: A Practical Guide . Oxford:Blackwell. Ridley, D. (2012).  The literature review: A step-by-step guide . 2nd edn. London: Sage. 

Chang, W. and Taylor, S.A. (2016), The Effectiveness of Customer Participation in New Product Development: A Meta-Analysis,  Journal of Marketing , American Marketing Association, Los Angeles, CA, Vol. 80 No. 1, pp. 47–64.

Tranfield, D., Denyer, D. & Smart, P. (2003). Towards a methodology for developing evidence-informed management knowledge by means of systematic review.  British Journal of Management , 14 (3), S. 207-222. doi:  https://doi.org/10.1111/1467-8551.00375

Webster, J., & Watson, R. T. (2002). Analyzing the Past to Prepare for the Future: Writing a Literature Review.  Management Information Systems Quarterly , 26(2), xiii-xxiii.  http://www.jstor.org/stable/4132319

Durach, C. F., Wieland, A. & Machuca, Jose. A. D. (2015). Antecedents and dimensions of supply chain robustness: a systematic literature review. International Journal of Physical Distribution & Logistics Management, 45(1/2), 118 – 137.

What is particularly good about this example is that search terms were defined by a number of experts and the review was conducted by three researchers working independently of one another. Furthermore, the search terms used have been very well extracted and the procedure of the literature selection very well described.

On the downside, the restriction to English-language literature brings the language bias into play, even though the authors consider it to be insignificant for the subject area.

Bos-Nehles, A., Renkema, M. & Janssen, M. (2017). HRM and innovative work behaviour: a systematic literature review. Personnel Review, 46(7), pp. 1228-1253

• Only very specific keywords used
• No precise information on how the review process was carried out (who reviewed articles?)
• Only journals with impact factor (publication bias)

Jia, F., Orzes, G., Sartor, M. & Nassimbeni, G. (2017). Global sourcing strategy and structure: towards a conceptual framework. International Journal of Operations & Production Management, 37(7), 840-864

• Research questions are explicitly presented
• Search string very detailed
• Exact description of the review process
• 2 persons conducted the review independently of each other

Franziska Klatt

[email protected]

+49 30 314-29778

Privacy notice: The TU Berlin offers a chat information service. If you enable it, your IP address and chat messages will be transmitted to external EU servers. more information

The chat is currently unavailable.

Please use our alternative contact options.

Systematic Reviews

Describes what is involved with conducting a systematic review of the literature for evidence-based public health and how the librarian is a partner in the process.

Several CDC librarians have special training in conducting literature searches for systematic reviews.  Literature searches for systematic reviews can take a few weeks to several months from planning to delivery.

Fill out a search request form here  or contact the Stephen B. Thacker CDC Library by email  [email protected] or telephone 404-639-1717.

Campbell Collaboration

Cochrane Collaboration

Eppi Centre

Joanna Briggs Institute

McMaster University

PRISMA Statement

Systematic Reviews – CRD’s Guide

Systematic Reviews of Health Promotion and Public Health Interventions

The Guide to Community Preventive Services

Look for systematic reviews that have already been published. 

• To ensure that the work has not already been done.
• To provides examples of search strategies for your topic

Look in PROSPERO for registered systematic reviews.

Search Cochrane and CRD-York for systematic reviews.

Search filter for finding systematic reviews in PubMed

Other search filters to locate systematic reviews

A systematic review attempts to collect and analyze all evidence that answers a specific question.  The question must be clearly defined and have inclusion and exclusion criteria. A broad and thorough search of the literature is performed and a critical analysis of the search results is reported and ultimately provides a current evidence-based answer  to the specific question.

Time:  According to Cochrane , it takes 18 months on average to complete a Systematic Review.

The average systematic review from beginning to end requires 18 months of work. “…to find out about a healthcare intervention it is worth searching research literature thoroughly to see if the answer is already known. This may require considerable work over many months…” ( Cochrane Collaboration )

Review Team: Team Members at minimum…

• Content expert
• 2 reviewers
• 1 tie breaker
• 1 statistician (meta-analysis)
• 1 economist if conducting an economic analysis
• *1 librarian (expert searcher) trained in systematic reviews

“Expert searchers are an important part of the systematic review team, crucial throughout the review process-from the development of the proposal and research question to publication.” ( McGowan & Sampson, 2005 )

*Ask your librarian to write a methods section regarding the search methods and to give them co-authorship. You may also want to consider providing a copy of one or all of the search strategies used in an appendix.

The Question to Be Answered: A clearly defined and specific question or questions with inclusion and exclusion criteria.

Written Protocol: Outline the study method, rationale, key questions, inclusion and exclusion criteria, literature searches, data abstraction and data management, analysis of quality of the individual studies, synthesis of data, and grading of the evidience for each key question.

Literature Searches:  Search for any systematic reviews that may already answer the key question(s).  Next, choose appropriate databases and conduct very broad, comprehensive searches.  Search strategies must be documented so that they can be duplicated.  The librarian is integral to this step of the process. Before your librarian creates a search strategy and starts searching in earnest you should write a detailed PICO question , determine the inclusion and exclusion criteria for your study, run a preliminary search, and have 2-4 articles that already fit the criteria for your review.

What is searched depends on the topic of the review but should include…

• At least 3 standard medical databases like PubMed/Medline, CINAHL, Embase, etc..
• At least 2 grey literature resources like Clinicaltrials.gov, COS Conference Papers Index, Grey Literature Report,  etc…

Citation Management: EndNote is a bibliographic management tools that assist researchers in managing citations.  The Stephen B. Thacker CDC Library oversees the site license for EndNote.

To request installation:   The library provides EndNote  to CDC staff under a site-wide license. Please use the ITSO Software Request Tool (SRT) and submit a request for the latest version (or upgraded version) of EndNote. Please be sure to include the computer name for the workstation where you would like to have the software installed.

EndNote Training:   CDC Library offers training on EndNote on a regular basis – both a basic and advanced course. To view the course descriptions and upcoming training dates, please visit the CDC Library training page .

For assistance with EndNote software, please contact [email protected]

Vendor Support and Services:   EndNote – Support and Services (Thomson Reuters)  EndNote – Tutorials and Live Online Classes (Thomson Reuters)

Getting Articles:

Articles can be obtained using DocExpress or by searching the electronic journals at the Stephen B. Thacker CDC Library.

IOM Standards for Systematic Reviews: Standard 3.1: Conduct a comprehensive systematic search for evidence

The goal of a systematic review search is to maximize recall and precision while keeping results manageable. Recall (sensitivity) is defined as the number of relevant reports identified divided by the total number of relevant reports in existence. Precision (specificity) is defined as the number of relevant reports identified divided by the total number of reports identified.

Issues to consider when creating a systematic review search:   

• All concepts are included in the strategy
• All appropriate subject headings are used
• Appropriate use of explosion
• Appropriate use of subheadings and floating subheadings
• Use of natural language (text words) in addition to controlled vocabulary terms
• Use of appropriate synonyms, acronyms, etc.
• Truncation and spelling variation as appropriate
• Appropriate use of limits such as language, years, etc.
• Field searching, publication type, author, etc.
• Boolean operators used appropriately
• Line errors: when searches are combined using line numbers, be sure the numbers refer to the searches intended
• Check indexing of relevant articles
• Search strategy adapted as needed for multiple databases
• Cochrane Handbook: Searching for Studies See Part 2, Chapter 6

A step-by-step guide to systematically identify all relevant animal studies

Materials listed in these guides are selected to provide awareness of quality public health literature and resources. A material’s inclusion does not necessarily represent the views of the U.S. Department of Health and Human Services (HHS), the Public Health Service (PHS), or the Centers for Disease Control and Prevention (CDC), nor does it imply endorsement of the material’s methods or findings. HHS, PHS, and CDC assume no responsibility for the factual accuracy of the items presented. The selection, omission, or content of items does not imply any endorsement or other position taken by HHS, PHS, and CDC. Opinion, findings, and conclusions expressed by the original authors of items included in these materials, or persons quoted therein, are strictly their own and are in no way meant to represent the opinion or views of HHS, PHS, or CDC. References to publications, news sources, and non-CDC Websites are provided solely for informational purposes and do not imply endorsement by HHS, PHS, or CDC.

Exit Notification / Disclaimer Policy

• The Centers for Disease Control and Prevention (CDC) cannot attest to the accuracy of a non-federal website.
• Linking to a non-federal website does not constitute an endorsement by CDC or any of its employees of the sponsors or the information and products presented on the website.
• You will be subject to the destination website's privacy policy when you follow the link.
• CDC is not responsible for Section 508 compliance (accessibility) on other federal or private website.

The Graduate Health & Life Sciences Research Library at Georgetown University Medical Center

Systematic reviews.

• Should I do a systematic review?
• Writing the Protocol
• Building a Systematic Search
• Where to Search
• Managing Project Data
• How can a DML librarian help?

Guides and Standards

• The Cochrane Handbook The Cochrane Handbook has become the de facto standard for planning and carrying out a systematic review. Chapter 6, Searching for Studies, is most helpful in planning your review.
• Finding What Works in Health Care: Standards for Systematic Reviews The IOM standards promote objective, transparent, and scientifically valid systematic reviews. They address the entire systematic review process, from locating, screening, and selecting studies for the review, to synthesizing the findings (including meta-analysis) and assessing the overall quality of the body of evidence, to producing the final review report.
• PRISMA Standards The Preferred Reporting Items for Systematic Reviews and Meta-Analyses is an evidence-based minimum set of items for reporting in systematic reviews and meta-analyses. A 27-item checklist, PRISMA focuses on randomized trials but can also be used as a basis for reporting systematic reviews of other types of research, particularly evaluations of interventions.

What is a systematic review?

A systematic literature review is a research methodology designed to answer a focused research question. Authors conduct a methodical and comprehensive literature synthesis focused on a well-formulated research question. Its aim is to identify and synthesize all of the scholarly research on a particular topic, including both published and unpublished studies. Systematic reviews are conducted in an unbiased, reproducible way to provide evidence for practice and policy-making and identify gaps in research.  Every step of the review, including the search, must be documented for reproducibility. 

Researchers in medicine may be most familiar with Cochrane Reviews, which synthesize randomized controlled trials to evaluate specific medical interventions. Systematic reviews are conducted in many other fields, though the type of evidence analyzed varies with the research question. 

When to use systematic review methodology

Systematic reviews require more time and manpower than traditional literature reviews. Before beginning a systematic review, researchers should address these questions:

Is there is enough literature published on the topic to warrant a review? 

Systematic reviews are designed to distill the evidence from many studies into actionable insights. Is there a body of evidence available to analyze, or does more primary research need to be done?

Can your research question be answered by a systematic review?

Systematic review questions should be specific and clearly defined. Questions that fit the PICO (problem/patient, intervention, comparison, outcome) format are usually well-suited for the systematic review methodology. The research question determines the search strategy, inclusion criteria, and data that you extract from the selected studies, so it should be clearly defined at the start of the review process.

Do you have a protocol outlining the review plan?

The protocol is the roadmap for the review project. A good protocol outlines study methodology, includes the rationale for the systematic review, and describes the key question broken into PICO components. It is also a good place to plan out inclusion/exclusion criteria, databases that will be searched, data abstraction and management methods, and how the studies will be assessed for methodological quality.

Do you have a team of experts?

A systematic review is team effort. Having multiple reviewers minimizes bias and strengthens analysis. Teams are often composed of subject experts, two or more literature screeners, a librarian to conduct the search, and a statistician to analyze the data. 

Do you have the time that it takes to properly conduct a systematic review?  

Systematic reviews typically take 12-18 months. 

Do you have a method for discerning bias?  

There are many types of bias, including selection, performance, & reporting bias, and assessing the risk of bias of individual studies is an important part of your study design.

Can you afford to have articles in languages other than English translated?  

You should include all relevant studies in your systematic review, regardless of the language they were published in, so as to avoid language bias. 

Which review is right for you?

If your project does not meet the above criteria, there are many more options for conducting a synthesis of the literature. The chart below highlights several review methodologies. Reproduced from: Grant MJ, Booth A. A typology of reviews: an analysis of 14 review types and associated methodologies. Health Info Libr J. 2009 Jun;26(2):91-108. doi: 10.1111/j.1471-1842.2009.00848.x  . Review. PubMed PMID: 19490148 

• Next: Writing the Protocol >>
• Last Updated: Apr 2, 2024 9:22 AM
• URL: https://guides.dml.georgetown.edu/systematicreviews

The Responsible Use of Electronic Resources policy governs the use of resources provided on these guides. © Dahlgren Memorial Library, Georgetown University Medical Center. Unless otherwise stated, these guides may be used for educational or academic purposes as long as proper attribution is given. Please seek permission for any modifications, adaptations, or for commercial purposes. Email [email protected] to request permission. Proper attribution includes: Written by or adapted from, Dahlgren Memorial Library, URL.

• Research Process

Systematic Literature Review or Literature Review?

• 3 minute read
• 43.6K views

Table of Contents

As a researcher, you may be required to conduct a literature review. But what kind of review do you need to complete? Is it a systematic literature review or a standard literature review? In this article, we’ll outline the purpose of a systematic literature review, the difference between literature review and systematic review, and other important aspects of systematic literature reviews.

What is a Systematic Literature Review?

The purpose of systematic literature reviews is simple. Essentially, it is to provide a high-level of a particular research question. This question, in and of itself, is highly focused to match the review of the literature related to the topic at hand. For example, a focused question related to medical or clinical outcomes.

The components of a systematic literature review are quite different from the standard literature review research theses that most of us are used to (more on this below). And because of the specificity of the research question, typically a systematic literature review involves more than one primary author. There’s more work related to a systematic literature review, so it makes sense to divide the work among two or three (or even more) researchers.

Your systematic literature review will follow very clear and defined protocols that are decided on prior to any review. This involves extensive planning, and a deliberately designed search strategy that is in tune with the specific research question. Every aspect of a systematic literature review, including the research protocols, which databases are used, and dates of each search, must be transparent so that other researchers can be assured that the systematic literature review is comprehensive and focused.

Most systematic literature reviews originated in the world of medicine science. Now, they also include any evidence-based research questions. In addition to the focus and transparency of these types of reviews, additional aspects of a quality systematic literature review includes:

• Clear and concise review and summary
• Comprehensive coverage of the topic
• Accessibility and equality of the research reviewed

Systematic Review vs Literature Review

The difference between literature review and systematic review comes back to the initial research question. Whereas the systematic review is very specific and focused, the standard literature review is much more general. The components of a literature review, for example, are similar to any other research paper. That is, it includes an introduction, description of the methods used, a discussion and conclusion, as well as a reference list or bibliography.

A systematic review, however, includes entirely different components that reflect the specificity of its research question, and the requirement for transparency and inclusion. For instance, the systematic review will include:

• Eligibility criteria for included research
• A description of the systematic research search strategy
• An assessment of the validity of reviewed research
• Interpretations of the results of research included in the review

As you can see, contrary to the general overview or summary of a topic, the systematic literature review includes much more detail and work to compile than a standard literature review. Indeed, it can take years to conduct and write a systematic literature review. But the information that practitioners and other researchers can glean from a systematic literature review is, by its very nature, exceptionally valuable.

This is not to diminish the value of the standard literature review. The importance of literature reviews in research writing is discussed in this article . It’s just that the two types of research reviews answer different questions, and, therefore, have different purposes and roles in the world of research and evidence-based writing.

Systematic Literature Review vs Meta Analysis

It would be understandable to think that a systematic literature review is similar to a meta analysis. But, whereas a systematic review can include several research studies to answer a specific question, typically a meta analysis includes a comparison of different studies to suss out any inconsistencies or discrepancies. For more about this topic, check out Systematic Review VS Meta-Analysis article.

Language Editing Plus

With Elsevier’s Language Editing Plus services , you can relax with our complete language review of your systematic literature review or literature review, or any other type of manuscript or scientific presentation. Our editors are PhD or PhD candidates, who are native-English speakers. Language Editing Plus includes checking the logic and flow of your manuscript, reference checks, formatting in accordance to your chosen journal and even a custom cover letter. Our most comprehensive editing package, Language Editing Plus also includes any English-editing needs for up to 180 days.

• Publication Recognition

How to Make a PowerPoint Presentation of Your Research Paper

• Manuscript Preparation

What is and How to Write a Good Hypothesis in Research?

You may also like.

Descriptive Research Design and Its Myriad Uses

Five Common Mistakes to Avoid When Writing a Biomedical Research Paper

Making Technical Writing in Environmental Engineering Accessible

To Err is Not Human: The Dangers of AI-assisted Academic Writing

When Data Speak, Listen: Importance of Data Collection and Analysis Methods

Choosing the Right Research Methodology: A Guide for Researchers

Why is data validation important in research?

Writing a good review article

Input your search keywords and press Enter.

• Locations and Hours
• UCLA Library
• Research Guides
• Biomedical Library Guides

Systematic Reviews

• Types of Literature Reviews

What Makes a Systematic Review Different from Other Types of Reviews?

• Planning Your Systematic Review
• Database Searching
• Creating the Search
• Search Filters and Hedges
• Grey Literature
• Managing and Appraising Results
• Further Resources

Reproduced from Grant, M. J. and Booth, A. (2009), A typology of reviews: an analysis of 14 review types and associated methodologies. Health Information & Libraries Journal, 26: 91–108. doi:10.1111/j.1471-1842.2009.00848.x

• << Previous: Home
• Next: Planning Your Systematic Review >>
• Last Updated: Apr 17, 2024 2:02 PM
• URL: https://guides.library.ucla.edu/systematicreviews

Systematic Reviews & Literature Reviews

Evidence synthesis: part 1.

This blog post is the first in a series exploring Evidence Synthesis . We’re going to start by looking at two types of evidence synthesis: literature reviews and systemic reviews . To help me with this topic I looked at a number of research guides from other institutions, e.g., Cornell University Libraries.

The Key Differences Between a Literature Review and a Systematic Review

Overall, while both literature reviews and systematic reviews involve reviewing existing research literature, systematic reviews adhere to more rigorous and transparent methods to minimize bias and provide robust evidence to inform decision-making in education and other fields. If you are interested in learning about other evidence synthesis this decision tree created by Cornell Libraries (Robinson, n.d.) is a nice visual introduction.

Along with exploring evidence synthesis I am also interested in generative A.I.   I want to be transparent about how I used A.I. to create the table above. I fed this prompt into ChatGPT:

“ List the differences between a literature review and a systemic review for a graduate student of education “

I wanted to see what it would produce. I reformatted the list into a table so that it would be easier to compare and contrast these two reviews much like the one created by Cornell University Libraries (Kibbee, 2024). I think ChatGPT did a pretty good job. I did have to do quite a bit of editing, and make sure that what was created matched what I already knew. There are things ChatGPT left out, for example time frames, and how many people are needed for a systemic review, but we can revisit that in a later post.

Kibbee, M. (2024, April 10). Libguides: A guide to evidence synthesis: Cornell University Library Evidence Synthesis Service. Cornell University Library. https://guides.library.cornell.edu/evidence-synthesis/intro

• Blog Archive 2009-2018
• Library Hours
• Library Salons
• Library Spaces
• Library Workshops
• Reference Desk Questions

Subscribe to the Bank Street Library Blog

An official website of the United States government

The .gov means it’s official. Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

The site is secure. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

• Publications
• Account settings

Preview improvements coming to the PMC website in October 2024. Learn More or Try it out now .

• Advanced Search
• Journal List
• J R Soc Med
• v.96(3); 2003 Mar

Five steps to conducting a systematic review

Regina kunz.

1 German Cochrane Centre, Freiburg and Department of Nephrology, Charité, Berlin, Germany

Jos Kleijnen

2 Centre for Reviews and Dissemination, York, UK

3 German Cochrane Centre, Freiburg, Germany

Systematic reviews and meta-analyses are a key element of evidence-based healthcare, yet they remain in some ways mysterious. Why did the authors select certain studies and reject others? What did they do to pool results? How did a bunch of insignificant findings suddenly become significant? This paper, along with a book 1 that goes into more detail, demystifies these and other related intrigues.

A review earns the adjective systematic if it is based on a clearly formulated question, identifies relevant studies, appraises their quality and summarizes the evidence by use of explicit methodology. It is the explicit and systematic approach that distinguishes systematic reviews from traditional reviews and commentaries. Whenever we use the term review in this paper it will mean a systematic review . Reviews should never be done in any other way.

In this paper we provide a step-by-step explanation—there are just five steps—of the methods behind reviewing, and the quality elements inherent in each step (Box 1). For purposes of illustration we use a published review concerning the safety of public water fluoridation, but we must emphasize that our subject is review methodology, not fluoridation.

EXAMPLE: SAFETY OF PUBLIC WATER FLUORIDATION

You are a public health professional in a locality that has public water fluoridation. For many years, your colleagues and you have believed that it improves dental health. Recently there has been pressure from various interest groups to consider the safety of this public health intervention because they fear that it is causing cancer. Public health decisions have been based on professional judgment and practical feasibility without explicit consideration of the scientific evidence. (This was yesterday; today the evidence is available in a York review 2 , 3 , identifiable on MEDLINE through the freely accessible PubMed clinical queries interface [ http://www.ncbi.nlm.nib.gov/entrez/query/static/clinical.html ], under ‘systematic reviews’.)

STEP 1: FRAMING THE QUESTION

The research question may initially be stated as a query in free form but reviewers prefer to pose it in a structured and explicit way. The relations between various components of the question and the structure of the research design are shown in Figure 1 . This paper focuses only on the question of safety related to the outcomes described below.

Structured questions for systematic reviews and relations between question components in a comparative study

Box 1 The steps in a systematic review

The problems to be addressed by the review should be specified in the form of clear, unambiguous and structured questions before beginning the review work. Once the review questions have been set, modifications to the protocol should be allowed only if alternative ways of defining the populations, interventions, outcomes or study designs become apparent

The search for studies should be extensive. Multiple resources (both computerized and printed) should be searched without language restrictions. The study selection criteria should flow directly from the review questions and be specified a priori . Reasons for inclusion and exclusion should be recorded

Study quality assessment is relevant to every step of a review. Question formulation (Step 1) and study selection criteria (Step 2) should describe the minimum acceptable level of design. Selected studies should be subjected to a more refined quality assessment by use of general critical appraisal guides and design-based quality checklists (Step 3). These detailed quality assessments will be used for exploring heterogeneity and informing decisions regarding suitability of meta-analysis (Step 4). In addition they help in assessing the strength of inferences and making recommendations for future research (Step 5)

Data synthesis consists of tabulation of study characteristics, quality and effects as well as use of statistical methods for exploring differences between studies and combining their effects (meta-analysis). Exploration of heterogeneity and its sources should be planned in advance (Step 3). If an overall meta-analysis cannot be done, subgroup meta-analysis may be feasible

The issues highlighted in each of the four steps above should be met. The risk of publication bias and related biases should be explored. Exploration for heterogeneity should help determine whether the overall summary can be trusted, and, if not, the effects observed in high-quality studies should be used for generating inferences. Any recommendations should be graded by reference to the strengths and weaknesses of the evidence

Free-form question

Is it safe to provide population-wide drinking water fluoridation to prevent caries?

Structured question

• The populations —Populations receiving drinking water sourced through a public water supply
• The interventions or exposures —Fluoridation of drinking water (natural or artificial) compared with non-fluoridated water
• The outcomes —Cancer is the main outcome of interest for the debate in your health authority
• The study designs —Comparative studies of any design examining the harmful outcomes in at least two population groups, one with fluoridated drinking water and the other without. Harmful outcomes can be rare and they may develop over a long time. There are considerable difficulties in designing and conducting safety studies to capture these outcomes, since a large number of people need to be observed over a long period. These circumstances demand observational, not randomized studies. With this background, systematic reviews on safety have to include evidence from studies with a range of designs.

STEP 2: IDENTIFYING RELEVANT PUBLICATIONS

To capture as many relevant citations as possible, a wide range of medical, environmental and scientific databases were searched to identify primary studies of the effects of water fluoridation. The electronic searches were supplemented by hand searching of Index Medicus and Excerpta Medica back to 1945. Furthermore, various internet engines were searched for web pages that might provide references. This effort resulted in 3246 citations from which relevant studies were selected for the review. Their potential relevance was examined, and 2511 citations were excluded as irrelevant. The full papers of the remaining 735 citations were assessed to select those primary studies in man that directly related to fluoride in drinking water supplies, comparing at least two groups. These criteria excluded 481 studies and left 254 in the review. They came from thirty countries, published in fourteen languages between 1939 and 2000. Of these studies 175 were relevant to the question of safety, of which 26 used cancer as an outcome.

STEP 3: ASSESSING STUDY QUALITY

Design threshold for study selection.

Adequate study design as a marker of quality, is listed as an inclusion criterion in Box 1. This approach is most applicable when the main source of evidence is randomized studies. However, randomized studies are almost impossible to conduct at community level for a public health intervention such as water fluoridation. Thus, systematic reviews assessing the safety of such interventions have to include evidence from a broader range of study designs. Consideration of the type and amount of research likely to be available led to inclusion of comparative studies of any design. In this way, selected studies provided information about the harmful effects of exposure to fluoridated water compared with non-exposure.

Quality assessment of safety studies

After studies of an acceptable design have been selected, their in-depth assessment for the risk of various biases allows us to gauge the quality of the evidence in a more refined way. Biases either exaggerate or underestimate the ‘true’ effect of an exposure. The objective of the included studies was to compare groups exposed to fluoridated drinking water and those without such exposure for rates of undesirable outcomes, without bias. Safety studies should ascertain exposures and outcomes in such a way that the risk of misclassification is minimized. The exposure is likely to be more accurately ascertained if the study was prospective rather than retrospective and if it was started soon after water fluoridation rather than later. The outcomes of those developing cancer (and remaining free of cancer) are likely to be more accurately ascertained if the follow-up was long and if the assessment was blind to exposure status.

When examining how the effect of exposure on outcome was established, reviewers assessed whether the comparison groups were similar in all respects other than their exposure to fluoridated water. This is because the other differences may be related to the outcomes of interest independent of the drinking-water fluoridation, and this would bias the comparison. For example, if the people exposed to fluoridated water had other risk factors that made them more prone to have cancer, the apparent association between exposure and outcome might be explained by the more frequent occurrence of these factors among the exposed group. The technical word for such defects is confounding. In a randomized study, confounding factors are expected to be roughly equally distributed between groups. In observational studies their distribution may be unequal. Primary researchers can statistically adjust for these differences, when estimating the effect of exposure on outcomes, by use of multivariable modelling.

Put simply, use of a prospective design, robust ascertainment of exposure and outcomes, and control for confounding are the generic issues one would look for in quality assessment of studies on safety. Consequently, studies may range from satisfactorily meeting quality criteria, to having some deficiencies, to not meeting the criteria at all, and they can be assigned to one of three prespecified quality categories as shown in Table 1 . A quality hierarchy can then be developed, based on the degree to which studies comply with the criteria. None of the studies on cancer were in the high-quality category, but this was because randomized studies were non-existent and control for confounding was not always ideal in the observational studies. There were 8 studies of moderate quality and 18 of low quality.

Description of quality assessment of studies on safety of public water fluoridation

STEP 4: SUMMARIZING THE EVIDENCE

To summarize the evidence from studies of variable design and quality is not easy. The original review 3 provides details of how the differences between study results were investigated and how they were summarized (with or without meta-analysis). This paper restricts itself to summarizing the findings narratively. The association between exposure to fluoridated water and cancer in general was examined in 26 studies. Of these, 10 examined all-cause cancer incidence or mortality, in 22 analyses. Of these, 11 analyses found a negative association (fewer cancers due to exposure), 9 found a positive one and 2 found no association. Only 2 studies reported statistically significant differences. Thus no clear association between water fluoridation and increased cancer incidence or mortality was apparent. Bone/joint and thyroid cancers were of particular concern because of fluoride uptake by these organs. Neither the 6 studies of osteosarcoma nor the 2 studies of thyroid cancer and water fluoridation revealed significant differences. Overall no association was detected between water fluoridation and mortality from any cancer. These findings were also borne out in the moderate-quality subgroup of studies.

STEP 5: INTERPRETING THE FINDINGS

In the fluoridation example, the focus was on the safety of a community-based public health intervention. The generally low quality of available studies means that the results must be interpreted with caution. However, the elaborate efforts in searching an unusually large number of databases provide some safeguard against missing relevant studies. Thus the evidence summarized in this review is likely to be as good as it will get in the foreseeable future. Cancer was the harmful outcome of most interest in this instance. No association was found between exposure to fluoridated water and specific cancers or all cancers. The interpretation of the results may be generally limited because of the low quality of studies, but the findings for the cancer outcomes are supported by the moderate-quality studies.

After having spent some time reading and understanding the review, you are impressed by the sheer amount of published work relevant to the question of safety. However, you are somewhat disappointed by the poor quality of the primary studies. Of course, examination of safety only makes sense in a context where the intervention has some beneficial effect. Benefit and harm have to be compared to provide the basis for decision making. On the issue of the beneficial effect of public water fluoridation, the review 3 reassures you that the health authority was correct in judging that fluoridation of drinking water prevents caries. From the review you also discovered that dental fluorosis (mottled teeth) was related to concentration of fluoride. When the interest groups raise the issue of safety again, you will be able to declare that there is no evidence to link cancer with drinking-water fluoridation; however, you will have to come clean about the risk of dental fluorosis, which appears to be dose dependent, and you may want to measure the fluoride concentration in the water supply and share this information with the interest groups.

The ability to quantify the safety concerns of your population through a review, albeit from studies of moderate to low quality, allows your health authority, the politicians and the public to consider the balance between beneficial and harmful effects of water fluoridation. Those who see the prevention of caries as of primary importance will favour fluoridation. Others, worried about the disfigurement of mottled teeth, may prefer other means of fluoride administration or even occasional treatment for dental caries. Whatever the opinions on this matter, you are able to reassure all parties that there is no evidence that fluoridation of drinking water increases the risk of cancer.

With increasing focus on generating guidance and recommendations for practice through systematic reviews, healthcare professionals need to understand the principles of preparing such reviews. Here we have provided a brief step-by-step explanation of the principles. Our book 1 describes them in detail.

• Open access
• Published: 19 April 2024

A scoping review of continuous quality improvement in healthcare system: conceptualization, models and tools, barriers and facilitators, and impact

• Aklilu Endalamaw 1 , 2 ,
• Resham B Khatri 1 , 3 ,
• Tesfaye Setegn Mengistu 1 , 2 ,
• Daniel Erku 1 , 4 , 5 ,
• Eskinder Wolka 6 ,
• Anteneh Zewdie 6 &
• Yibeltal Assefa 1  

BMC Health Services Research volume  24 , Article number:  487 ( 2024 ) Cite this article

732 Accesses

Metrics details

The growing adoption of continuous quality improvement (CQI) initiatives in healthcare has generated a surge in research interest to gain a deeper understanding of CQI. However, comprehensive evidence regarding the diverse facets of CQI in healthcare has been limited. Our review sought to comprehensively grasp the conceptualization and principles of CQI, explore existing models and tools, analyze barriers and facilitators, and investigate its overall impacts.

This qualitative scoping review was conducted using Arksey and O’Malley’s methodological framework. We searched articles in PubMed, Web of Science, Scopus, and EMBASE databases. In addition, we accessed articles from Google Scholar. We used mixed-method analysis, including qualitative content analysis and quantitative descriptive for quantitative findings to summarize findings and PRISMA extension for scoping reviews (PRISMA-ScR) framework to report the overall works.

A total of 87 articles, which covered 14 CQI models, were included in the review. While 19 tools were used for CQI models and initiatives, Plan-Do-Study/Check-Act cycle was the commonly employed model to understand the CQI implementation process. The main reported purposes of using CQI, as its positive impact, are to improve the structure of the health system (e.g., leadership, health workforce, health technology use, supplies, and costs), enhance healthcare delivery processes and outputs (e.g., care coordination and linkages, satisfaction, accessibility, continuity of care, safety, and efficiency), and improve treatment outcome (reduce morbidity and mortality). The implementation of CQI is not without challenges. There are cultural (i.e., resistance/reluctance to quality-focused culture and fear of blame or punishment), technical, structural (related to organizational structure, processes, and systems), and strategic (inadequate planning and inappropriate goals) related barriers that were commonly reported during the implementation of CQI.

Conclusions

Implementing CQI initiatives necessitates thoroughly comprehending key principles such as teamwork and timeline. To effectively address challenges, it’s crucial to identify obstacles and implement optimal interventions proactively. Healthcare professionals and leaders need to be mentally equipped and cognizant of the significant role CQI initiatives play in achieving purposes for quality of care.

Peer Review reports

Continuous quality improvement (CQI) initiative is a crucial initiative aimed at enhancing quality in the health system that has gradually been adopted in the healthcare industry. In the early 20th century, Shewhart laid the foundation for quality improvement by describing three essential steps for process improvement: specification, production, and inspection [ 1 , 2 ]. Then, Deming expanded Shewhart’s three-step model into ‘plan, do, study/check, and act’ (PDSA or PDCA) cycle, which was applied to management practices in Japan in the 1950s [ 3 ] and was gradually translated into the health system. In 1991, Kuperman applied a CQI approach to healthcare, comprising selecting a process to be improved, assembling a team of expert clinicians that understands the process and the outcomes, determining key steps in the process and expected outcomes, collecting data that measure the key process steps and outcomes, and providing data feedback to the practitioners [ 4 ]. These philosophies have served as the baseline for the foundation of principles for continuous improvement [ 5 ].

Continuous quality improvement fosters a culture of continuous learning, innovation, and improvement. It encourages proactive identification and resolution of problems, promotes employee engagement and empowerment, encourages trust and respect, and aims for better quality of care [ 6 , 7 ]. These characteristics drive the interaction of CQI with other quality improvement projects, such as quality assurance and total quality management [ 8 ]. Quality assurance primarily focuses on identifying deviations or errors through inspections, audits, and formal reviews, often settling for what is considered ‘good enough’, rather than pursuing the highest possible standards [ 9 , 10 ], while total quality management is implemented as the management philosophy and system to improve all aspects of an organization continuously [ 11 ].

Continuous quality improvement has been implemented to provide quality care. However, providing effective healthcare is a complicated and complex task in achieving the desired health outcomes and the overall well-being of individuals and populations. It necessitates tackling issues, including access, patient safety, medical advances, care coordination, patient-centered care, and quality monitoring [ 12 , 13 ], rooted long ago. It is assumed that the history of quality improvement in healthcare started in 1854 when Florence Nightingale introduced quality improvement documentation [ 14 ]. Over the passing decades, Donabedian introduced structure, processes, and outcomes as quality of care components in 1966 [ 15 ]. More comprehensively, the Institute of Medicine in the United States of America (USA) has identified effectiveness, efficiency, equity, patient-centredness, safety, and timeliness as the components of quality of care [ 16 ]. Moreover, quality of care has recently been considered an integral part of universal health coverage (UHC) [ 17 ], which requires initiatives to mobilise essential inputs [ 18 ].

While the overall objective of CQI in health system is to enhance the quality of care, it is important to note that the purposes and principles of CQI can vary across different contexts [ 19 , 20 ]. This variation has sparked growing research interest. For instance, a review of CQI approaches for capacity building addressed its role in health workforce development [ 21 ]. Another systematic review, based on random-controlled design studies, assessed the effectiveness of CQI using training as an intervention and the PDSA model [ 22 ]. As a research gap, the former review was not directly related to the comprehensive elements of quality of care, while the latter focused solely on the impact of training using the PDSA model, among other potential models. Additionally, a review conducted in 2015 aimed to identify barriers and facilitators of CQI in Canadian contexts [ 23 ]. However, all these reviews presented different perspectives and investigated distinct outcomes. This suggests that there is still much to explore in terms of comprehensively understanding the various aspects of CQI initiatives in healthcare.

As a result, we conducted a scoping review to address several aspects of CQI. Scoping reviews serve as a valuable tool for systematically mapping the existing literature on a specific topic. They are instrumental when dealing with heterogeneous or complex bodies of research. Scoping reviews provide a comprehensive overview by summarizing and disseminating findings across multiple studies, even when evidence varies significantly [ 24 ]. In our specific scoping review, we included various types of literature, including systematic reviews, to enhance our understanding of CQI.

This scoping review examined how CQI is conceptualized and measured and investigated models and tools for its application while identifying implementation challenges and facilitators. It also analyzed the purposes and impact of CQI on the health systems, providing valuable insights for enhancing healthcare quality.

Protocol registration and results reporting

Protocol registration for this scoping review was not conducted. Arksey and O’Malley’s methodological framework was utilized to conduct this scoping review [ 25 ]. The scoping review procedures start by defining the research questions, identifying relevant literature, selecting articles, extracting data, and summarizing the results. The review findings are reported using the PRISMA extension for a scoping review (PRISMA-ScR) [ 26 ]. McGowan and colleagues also advised researchers to report findings from scoping reviews using PRISMA-ScR [ 27 ].

Defining the research problems

This review aims to comprehensively explore the conceptualization, models, tools, barriers, facilitators, and impacts of CQI within the healthcare system worldwide. Specifically, we address the following research questions: (1) How has CQI been defined across various contexts? (2) What are the diverse approaches to implementing CQI in healthcare settings? (3) Which tools are commonly employed for CQI implementation ? (4) What barriers hinder and facilitators support successful CQI initiatives? and (5) What effects CQI initiatives have on the overall care quality?

Information source and search strategy

We conducted the search in PubMed, Web of Science, Scopus, and EMBASE databases, and the Google Scholar search engine. The search terms were selected based on three main distinct concepts. One group was CQI-related terms. The second group included terms related to the purpose for which CQI has been implemented, and the third group included processes and impact. These terms were selected based on the Donabedian framework of structure, process, and outcome [ 28 ]. Additionally, the detailed keywords were recruited from the primary health framework, which has described lists of dimensions under process, output, outcome, and health system goals of any intervention for health [ 29 ]. The detailed search strategy is presented in the Supplementary file 1 (Search strategy). The search for articles was initiated on August 12, 2023, and the last search was conducted on September 01, 2023.

Eligibility criteria and article selection

Based on the scoping review’s population, concept, and context frameworks [ 30 ], the population included any patients or clients. Additionally, the concepts explored in the review encompassed definitions, implementation, models, tools, barriers, facilitators, and impacts of CQI. Furthermore, the review considered contexts at any level of health systems. We included articles if they reported results of qualitative or quantitative empirical study, case studies, analytic or descriptive synthesis, any review, and other written documents, were published in peer-reviewed journals, and were designed to address at least one of the identified research questions or one of the identified implementation outcomes or their synonymous taxonomy as described in the search strategy. Based on additional contexts, we included articles published in English without geographic and time limitations. We excluded articles with abstracts only, conference abstracts, letters to editors, commentators, and corrections.

We exported all citations to EndNote x20 to remove duplicates and screen relevant articles. The article selection process includes automatic duplicate removal by using EndNote x20, unmatched title and abstract removal, citation and abstract-only materials removal, and full-text assessment. The article selection process was mainly conducted by the first author (AE) and reported to the team during the weekly meetings. The first author encountered papers that caused confusion regarding whether to include or exclude them and discussed them with the last author (YA). Then, decisions were ultimately made. Whenever disagreements happened, they were resolved by discussion and reconsideration of the review questions in relation to the written documents of the article. Further statistical analysis, such as calculating Kappa, was not performed to determine article inclusion or exclusion.

Data extraction and data items

We extracted first author, publication year, country, settings, health problem, the purpose of the study, study design, types of intervention if applicable, CQI approaches/steps if applicable, CQI tools and procedures if applicable, and main findings using a customized Microsoft Excel form.

Summarizing and reporting the results

The main findings were summarized and described based on the main themes, including concepts under conceptualizing, principles, teams, timelines, models, tools, barriers, facilitators, and impacts of CQI. Results-based convergent synthesis, achieved through mixed-method analysis, involved content analysis to identify the thematic presentation of findings. Additionally, a narrative description was used for quantitative findings, aligning them with the appropriate theme. The authors meticulously reviewed the primary findings from each included material and contextualized these findings concerning the main themes1. This approach provides a comprehensive understanding of complex interventions and health systems, acknowledging quantitative and qualitative evidence.

Search results

A total of 11,251 documents were identified from various databases: SCOPUS ( n  = 4,339), PubMed ( n  = 2,893), Web of Science ( n  = 225), EMBASE ( n  = 3,651), and Google Scholar ( n  = 143). After removing duplicates ( n  = 5,061), 6,190 articles were evaluated by title and abstract. Subsequently, 208 articles were assessed for full-text eligibility. Following the eligibility criteria, 121 articles were excluded, leaving 87 included in the current review (Fig.  1 ).

Article selection process

Operationalizing continuous quality improvement

Continuous Quality Improvement (CQI) is operationalized as a cyclic process that requires commitment to implementation, teamwork, time allocation, and celebrating successes and failures.

CQI is a cyclic ongoing process that is followed reflexive, analytical and iterative steps, including identifying gaps, generating data, developing and implementing action plans, evaluating performance, providing feedback to implementers and leaders, and proposing necessary adjustments [ 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 ].

CQI requires committing to the philosophy, involving continuous improvement [ 19 , 38 ], establishing a mission statement [ 37 ], and understanding quality definition [ 19 ].

CQI involves a wide range of patient-oriented measures and performance indicators, specifically satisfying internal and external customers, developing quality assurance, adopting common quality measures, and selecting process measures [ 8 , 19 , 35 , 36 , 37 , 39 , 40 ].

CQI requires celebrating success and failure without personalization, leading each team member to develop error-free attitudes [ 19 ]. Success and failure are related to underlying organizational processes and systems as causes of failure rather than blaming individuals [ 8 ] because CQI is process-focused based on collaborative, data-driven, responsive, rigorous and problem-solving statistical analysis [ 8 , 19 , 38 ]. Furthermore, a gap or failure opens another opportunity for establishing a data-driven learning organization [ 41 ].

CQI cannot be implemented without a CQI team [ 8 , 19 , 37 , 39 , 42 , 43 , 44 , 45 , 46 ]. A CQI team comprises individuals from various disciplines, often comprising a team leader, a subject matter expert (physician or other healthcare provider), a data analyst, a facilitator, frontline staff, and stakeholders [ 39 , 43 , 47 , 48 , 49 ]. It is also important to note that inviting stakeholders or partners as part of the CQI support intervention is crucial [ 19 , 38 , 48 ].

The timeline is another distinct feature of CQI because the results of CQI vary based on the implementation duration of each cycle [ 35 ]. There is no specific time limit for CQI implementation, although there is a general consensus that a cycle of CQI should be relatively short [ 35 ]. For instance, a CQI implementation took 2 months [ 42 ], 4 months [ 50 ], 9 months [ 51 , 52 ], 12 months [ 53 , 54 , 55 ], and one year and 5 months [ 49 ] duration to achieve the desired positive outcome, while bi-weekly [ 47 ] and monthly data reviews and analyses [ 44 , 48 , 56 ], and activities over 3 months [ 57 ] have also resulted in a positive outcome.

Continuous quality improvement models and tools

There have been several models are utilized. The Plan-Do-Study/Check-Act cycle is a stepwise process involving project initiation, situation analysis, root cause identification, solution generation and selection, implementation, result evaluation, standardization, and future planning [ 7 , 36 , 37 , 45 , 47 , 48 , 49 , 50 , 51 , 53 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 ]. The FOCUS-PDCA cycle enhances the PDCA process by adding steps to find and improve a process (F), organize a knowledgeable team (O), clarify the process (C), understand variations (U), and select improvements (S) [ 55 , 71 , 72 , 73 ]. The FADE cycle involves identifying a problem (Focus), understanding it through data analysis (Analyze), devising solutions (Develop), and implementing the plan (Execute) [ 74 ]. The Logic Framework involves brainstorming to identify improvement areas, conducting root cause analysis to develop a problem tree, logically reasoning to create an objective tree, formulating the framework, and executing improvement projects [ 75 ]. Breakthrough series approach requires CQI teams to meet in quarterly collaborative learning sessions, share learning experiences, and continue discussion by telephone and cross-site visits to strengthen learning and idea exchange [ 47 ]. Another CQI model is the Lean approach, which has been conducted with Kaizen principles [ 52 ], 5 S principles, and the Six Sigma model. The 5 S (Sort, Set/Straighten, Shine, Standardize, Sustain) systematically organises and improves the workplace, focusing on sorting, setting order, shining, standardizing, and sustaining the improvement [ 54 , 76 ]. Kaizen principles guide CQI by advocating for continuous improvement, valuing all ideas, solving problems, focusing on practical, low-cost improvements, using data to drive change, acknowledging process defects, reducing variability and waste, recognizing every interaction as a customer-supplier relationship, empowering workers, responding to all ideas, and maintaining a disciplined workplace [ 77 ]. Lean Six Sigma, a CQI model, applies the DMAIC methodology, which involves defining (D) and measuring the problem (M), analyzing root causes (A), improving by finding solutions (I), and controlling by assessing process stability (C) [ 78 , 79 ]. The 5 C-cyclic model (consultation, collection, consideration, collaboration, and celebration), the first CQI framework for volunteer dental services in Aboriginal communities, ensures quality care based on community needs [ 80 ]. One study used meetings involving activities such as reviewing objectives, assigning roles, discussing the agenda, completing tasks, retaining key outputs, planning future steps, and evaluating the meeting’s effectiveness [ 81 ].

Various tools are involved in the implementation or evaluation of CQI initiatives: checklists [ 53 , 82 ], flowcharts [ 81 , 82 , 83 ], cause-and-effect diagrams (fishbone or Ishikawa diagrams) [ 60 , 62 , 79 , 81 , 82 ], fuzzy Pareto diagram [ 82 ], process maps [ 60 ], time series charts [ 48 ], why-why analysis [ 79 ], affinity diagrams and multivoting [ 81 ], and run chart [ 47 , 48 , 51 , 60 , 84 ], and others mentioned in the table (Table  1 ).

Barriers and facilitators of continuous quality improvement implementation

Implementing CQI initiatives is determined by various barriers and facilitators, which can be thematized into four dimensions. These dimensions are cultural, technical, structural, and strategic dimensions.

Continuous quality improvement initiatives face various cultural, strategic, technical, and structural barriers. Cultural dimension barriers involve resistance to change (e.g., not accepting online technology), lack of quality-focused culture, staff reporting apprehensiveness, and fear of blame or punishment [ 36 , 41 , 85 , 86 ]. The technical dimension barriers of CQI can include various factors that hinder the effective implementation and execution of CQI processes [ 36 , 86 , 87 , 88 , 89 ]. Structural dimension barriers of CQI arise from the organization structure, process, and systems that can impede the effective implementation and sustainability of CQI [ 36 , 85 , 86 , 87 , 88 ]. Strategic dimension barriers are, for example, the inability to select proper CQI goals and failure to integrate CQI into organizational planning and goals [ 36 , 85 , 86 , 87 , 88 , 90 ].

Facilitators are also grouped to cultural, structural, technical, and strategic dimensions to provide solutions to CQI barriers. Cultural challenges were addressed by developing a group culture to CQI and other rewards [ 39 , 41 , 80 , 85 , 86 , 87 , 90 , 91 , 92 ]. Technical facilitators are pivotal to improving technical barriers [ 39 , 42 , 53 , 69 , 86 , 90 , 91 ]. Structural-related facilitators are related to improving communication, infrastructure, and systems [ 86 , 92 , 93 ]. Strategic dimension facilitators include strengthening leadership and improving decision-making skills [ 43 , 53 , 67 , 86 , 87 , 92 , 94 , 95 ] (Table  2 ).

Impact of continuous quality improvement

Continuous quality improvement initiatives can significantly impact the quality of healthcare in a wide range of health areas, focusing on improving structure, the health service delivery process and improving client wellbeing and reducing mortality.

Structure components

These are health leadership, financing, workforce, technology, and equipment and supplies. CQI has improved planning, monitoring and evaluation [ 48 , 53 ], and leadership and planning [ 48 ], indicating improvement in leadership perspectives. Implementing CQI in primary health care (PHC) settings has shown potential for maintaining or reducing operation costs [ 67 ]. Findings from another study indicate that the costs associated with implementing CQI interventions per facility ranged from approximately $2,000 to $10,500 per year, with an average cost of approximately $10 to $60 per admitted client [ 57 ]. However, based on model predictions, the average cost savings after implementing CQI were estimated to be $5430 [ 31 ]. CQI can also be applied to health workforce development [ 32 ]. CQI in the institutional system improved medical education [ 66 , 96 , 97 ], human resources management [ 53 ], motivated staffs [ 76 ], and increased staff health awareness [ 69 ], while concerns raised about CQI impartiality, independence, and public accountability [ 96 ]. Regarding health technology, CQI also improved registration and documentation [ 48 , 53 , 98 ]. Furthermore, the CQI initiatives increased cleanliness [ 54 ] and improved logistics, supplies, and equipment [ 48 , 53 , 68 ].

Process and output components

The process component focuses on the activities and actions involved in delivering healthcare services.

Service delivery

CQI interventions improved service delivery [ 53 , 56 , 99 ], particularly a significant 18% increase in the overall quality of service performance [ 48 ], improved patient counselling, adherence to appropriate procedures, and infection prevention [ 48 , 68 ], and optimised workflow [ 52 ].

Coordination and collaboration

CQI initiatives improved coordination and collaboration through collecting and analysing data, onsite technical support, training, supportive supervision [ 53 ] and facilitating linkages between work processes and a quality control group [ 65 ].

Patient satisfaction

The CQI initiatives increased patient satisfaction and improved quality of life by optimizing care quality management, improving the quality of clinical nursing, reducing nursing defects and enhancing the wellbeing of clients [ 54 , 76 , 100 ], although CQI was not associated with changes in adolescent and young adults’ satisfaction [ 51 ].

CQI initiatives reduced medication error reports from 16 to 6 [ 101 ], and it significantly reduced the administration of inappropriate prophylactic antibiotics [ 44 ], decreased errors in inpatient care [ 52 ], decreased the overall episiotomy rate from 44.5 to 33.3% [ 83 ], reduced the overall incidence of unplanned endotracheal extubation [ 102 ], improving appropriate use of computed tomography angiography [ 103 ], and appropriate diagnosis and treatment selection [ 47 ].

Continuity of care

CQI initiatives effectively improve continuity of care by improving client and physician interaction. For instance, provider continuity levels showed a 64% increase [ 55 ]. Modifying electronic medical record templates, scheduling, staff and parental education, standardization of work processes, and birth to 1-year age-specific incentives in post-natal follow-up care increased continuity of care to 74% in 2018 compared to baseline 13% in 2012 [ 84 ].

The CQI initiative yielded enhanced efficiency in the cardiac catheterization laboratory, as evidenced by improved punctuality in procedure starts and increased efficiency in manual sheath-pulls inside [ 78 ].

Accessibility

CQI initiatives were effective in improving accessibility in terms of increasing service coverage and utilization rate. For instance, screening for cigarettes, nutrition counselling, folate prescription, maternal care, immunization coverage [ 53 , 81 , 104 , 105 ], reducing the percentage of non-attending patients to surgery to 0.9% from the baseline 3.9% [ 43 ], increasing Chlamydia screening rates from 29 to 60% [ 45 ], increasing HIV care continuum coverage [ 51 , 59 , 60 ], increasing in the uptake of postpartum long-acting reversible contraceptive use from 6.9% at the baseline to 25.4% [ 42 ], increasing post-caesarean section prophylaxis from 36 to 89% [ 62 ], a 31% increase of kangaroo care practice [ 50 ], and increased follow-up [ 65 ]. Similarly, the QI intervention increased the quality of antenatal care by 29.3%, correct partograph use by 51.7%, and correct active third-stage labour management, a 19.6% improvement from the baseline, but not significantly associated with improvement in contraceptive service uptake [ 61 ].

Timely access

CQI interventions improved the time care provision [ 52 ], and reduced waiting time [ 62 , 74 , 76 , 106 ]. For instance, the discharge process waiting time in the emergency department decreased from 76 min to 22 min [ 79 ]. It also reduced mean postprocedural length of stay from 2.8 days to 2.0 days [ 31 ].

Acceptability

Acceptability of CQI by healthcare providers was satisfactory. For instance, 88% of the faculty, 64% of the residents, and 82% of the staff believed CQI to be useful in the healthcare clinic [ 107 ].

Outcome components

Morbidity and mortality.

CQI efforts have demonstrated better management outcomes among diabetic patients [ 40 ], patients with oral mucositis [ 71 ], and anaemic patients [ 72 ]. It has also reduced infection rate in post-caesarean Sect. [ 62 ], reduced post-peritoneal dialysis peritonitis [ 49 , 108 ], and prevented pressure ulcers [ 70 ]. It is explained by peritonitis incidence from once every 40.1 patient months at baseline to once every 70.8 patient months after CQI [ 49 ] and a 63% reduction in pressure ulcer prevalence within 2 years from 2008 to 2010 [ 70 ]. Furthermore, CQI initiatives significantly reduced in-hospital deaths [ 31 ] and increased patient survival rates [ 108 ]. Figure  2 displays the overall process of the CQI implementations.

The overall mechanisms of continuous quality improvement implementation

In this review, we examined the fundamental concepts and principles underlying CQI, the factors that either hinder or assist in its successful application and implementation, and the purpose of CQI in enhancing quality of care across various health issues.

Our findings have brought attention to the application and implementation of CQI, emphasizing its underlying concepts and principles, as evident in the existing literature [ 31 , 32 , 33 , 34 , 35 , 36 , 39 , 40 , 43 , 45 , 46 ]. Continuous quality improvement has shared with the principles of continuous improvement, such as a customer-driven focus, effective leadership, active participation of individuals, a process-oriented approach, systematic implementation, emphasis on design improvement and prevention, evidence-based decision-making, and fostering partnership [ 5 ]. Moreover, Deming’s 14 principles laid the foundation for CQI principles [ 109 ]. These principles have been adapted and put into practice in various ways: ten [ 19 ] and five [ 38 ] principles in hospitals, five principles for capacity building [ 38 ], and two principles for medication error prevention [ 41 ]. As a principle, the application of CQI can be process-focused [ 8 , 19 ] or impact-focused [ 38 ]. Impact-focused CQI focuses on achieving specific outcomes or impacts, whereas process-focused CQI prioritizes and improves the underlying processes and systems. These principles complement each other and can be utilized based on the objectives of quality improvement initiatives in healthcare settings. Overall, CQI is an ongoing educational process that requires top management’s involvement, demands coordination across departments, encourages the incorporation of views beyond clinical area, and provides non-judgemental evidence based on objective data [ 110 ].

The current review recognized that it was not easy to implement CQI. It requires reasonable utilization of various models and tools. The application of each tool can be varied based on the studied health problem and the purpose of CQI initiative [ 111 ], varied in context, content, structure, and usability [ 112 ]. Additionally, overcoming the cultural, technical, structural, and strategic-related barriers. These barriers have emerged from clinical staff, managers, and health systems perspectives. Of the cultural obstacles, staff non-involvement, resistance to change, and reluctance to report error were staff-related. In contrast, others, such as the absence of celebration for success and hierarchical and rational culture, may require staff and manager involvement. Staff members may exhibit reluctance in reporting errors due to various cultural factors, including lack of trust, hierarchical structures, fear of retribution, and a blame-oriented culture. These challenges pose obstacles to implementing standardized CQI practices, as observed, for instance, in community pharmacy settings [ 85 ]. The hierarchical culture, characterized by clearly defined levels of power, authority, and decision-making, posed challenges to implementing CQI initiatives in public health [ 41 , 86 ]. Although rational culture, a type of organizational culture, emphasizes logical thinking and rational decision-making, it can also create challenges for CQI implementation [ 41 , 86 ] because hierarchical and rational cultures, which emphasize bureaucratic norms and narrow definitions of achievement, were found to act as barriers to the implementation of CQI [ 86 ]. These could be solved by developing a shared mindset and collective commitment, establishing a shared purpose, developing group norms, and cultivating psychological preparedness among staff, managers, and clients to implement and sustain CQI initiatives. Furthermore, reversing cultural-related barriers necessitates cultural-related solutions: development of a culture and group culture to CQI [ 41 , 86 ], positive comprehensive perception [ 91 ], commitment [ 85 ], involving patients, families, leaders, and staff [ 39 , 92 ], collaborating for a common goal [ 80 , 86 ], effective teamwork [ 86 , 87 ], and rewarding and celebrating successes [ 80 , 90 ].

The technical dimension barriers of CQI can include inadequate capitalization of a project and insufficient support for CQI facilitators and data entry managers [ 36 ], immature electronic medical records or poor information systems [ 36 , 86 ], and the lack of training and skills [ 86 , 87 , 88 ]. These challenges may cause the CQI team to rely on outdated information and technologies. The presence of barriers on the technical dimension may challenge the solid foundation of CQI expertise among staff, the ability to recognize opportunities for improvement, a comprehensive understanding of how services are produced and delivered, and routine use of expertise in daily work. Addressing these technical barriers requires knowledge creation activities (training, seminar, and education) [ 39 , 42 , 53 , 69 , 86 , 90 , 91 ], availability of quality data [ 86 ], reliable information [ 92 ], and a manual-online hybrid reporting system [ 85 ].

Structural dimension barriers of CQI include inadequate communication channels and lack of standardized process, specifically weak physician-to-physician synergies [ 36 ], lack of mechanisms for disseminating knowledge and limited use of communication mechanisms [ 86 ]. Lack of communication mechanism endangers sharing ideas and feedback among CQI teams, leading to misunderstandings, limited participation and misinterpretations, and a lack of learning [ 113 ]. Knowledge translation facilitates the co-production of research, subsequent diffusion of knowledge, and the developing stakeholder’s capacity and skills [ 114 ]. Thus, the absence of a knowledge translation mechanism may cause missed opportunities for learning, inefficient problem-solving, and limited creativity. To overcome these challenges, organizations should establish effective communication and information systems [ 86 , 93 ] and learning systems [ 92 ]. Though CQI and knowledge translation have interacted with each other, it is essential to recognize that they are distinct. CQI focuses on process improvement within health care systems, aiming to optimize existing processes, reduce errors, and enhance efficiency.

In contrast, knowledge translation bridges the gap between research evidence and clinical practice, translating research findings into actionable knowledge for practitioners. While both CQI and knowledge translation aim to enhance health care quality and patient outcomes, they employ different strategies: CQI utilizes tools like Plan-Do-Study-Act cycles and statistical process control, while knowledge translation involves knowledge synthesis and dissemination. Additionally, knowledge translation can also serve as a strategy to enhance CQI. Both concepts share the same principle: continuous improvement is essential for both. Therefore, effective strategies on the structural dimension may build efficient and effective steering councils, information systems, and structures to diffuse learning throughout the organization.

Strategic factors, such as goals, planning, funds, and resources, determine the overall purpose of CQI initiatives. Specific barriers were improper goals and poor planning [ 36 , 86 , 88 ], fragmentation of quality assurance policies [ 87 ], inadequate reinforcement to staff [ 36 , 90 ], time constraints [ 85 , 86 ], resource inadequacy [ 86 ], and work overload [ 86 ]. These barriers can be addressed through strengthening leadership [ 86 , 87 ], CQI-based mentoring [ 94 ], periodic monitoring, supportive supervision and coaching [ 43 , 53 , 87 , 92 , 95 ], participation, empowerment, and accountability [ 67 ], involving all stakeholders in decision-making [ 86 , 87 ], a provider-payer partnership [ 64 ], and compensating staff for after-hours meetings on CQI [ 85 ]. The strategic dimension, characterized by a strategic plan and integrated CQI efforts, is devoted to processes that are central to achieving strategic priorities. Roles and responsibilities are defined in terms of integrated strategic and quality-related goals [ 115 ].

The utmost goal of CQI has been to improve the quality of care, which is usually revealed by structure, process, and outcome. After resolving challenges and effectively using tools and running models, the goal of CQI reflects the ultimate reason and purpose of its implementation. First, effectively implemented CQI initiatives can improve leadership, health financing, health workforce development, health information technology, and availability of supplies as the building blocks of a health system [ 31 , 48 , 53 , 68 , 98 ]. Second, effectively implemented CQI initiatives improved care delivery process (counselling, adherence with standards, coordination, collaboration, and linkages) [ 48 , 53 , 65 , 68 ]. Third, the CQI can improve outputs of healthcare delivery, such as satisfaction, accessibility (timely access, utilization), continuity of care, safety, efficiency, and acceptability [ 52 , 54 , 55 , 76 , 78 ]. Finally, the effectiveness of the CQI initiatives has been tested in enhancing responses related to key aspects of the HIV response, maternal and child health, non-communicable disease control, and others (e.g., surgery and peritonitis). However, it is worth noting that CQI initiative has not always been effective. For instance, CQI using a two- to nine-times audit cycle model through systems assessment tools did not bring significant change to increase syphilis testing performance [ 116 ]. This study was conducted within the context of Aboriginal and Torres Strait Islander people’s primary health care settings. Notably, ‘the clinics may not have consistently prioritized syphilis testing performance in their improvement strategies, as facilitated by the CQI program’ [ 116 ]. Additionally, by applying CQI-based mentoring, uptake of facility-based interventions was not significantly improved, though it was effective in increasing community health worker visits during pregnancy and the postnatal period, knowledge about maternal and child health and exclusive breastfeeding practice, and HIV disclosure status [ 117 ]. The study conducted in South Africa revealed no significant association between the coverage of facility-based interventions and Continuous Quality Improvement (CQI) implementation. This lack of association was attributed to the already high antenatal and postnatal attendance rates in both control and intervention groups at baseline, leaving little room for improvement. Additionally, the coverage of HIV interventions remained consistently high throughout the study period [ 117 ].

Regarding health care and policy implications, CQI has played a vital role in advancing PHC and fostering the realization of UHC goals worldwide. The indicators found in Donabedian’s framework that are positively influenced by CQI efforts are comparable to those included in the PHC performance initiative’s conceptual framework [ 29 , 118 , 119 ]. It is clearly explained that PHC serves as the roadmap to realizing the vision of UHC [ 120 , 121 ]. Given these circumstances, implementing CQI can contribute to the achievement of PHC principles and the objectives of UHC. For instance, by implementing CQI methods, countries have enhanced the accessibility, affordability, and quality of PHC services, leading to better health outcomes for their populations. CQI has facilitated identifying and resolving healthcare gaps and inefficiencies, enabling countries to optimize resource allocation and deliver more effective and patient-centered care. However, it is crucial to recognize that the successful implementation of Continuous Quality Improvement (CQI) necessitates optimizing the duration of each cycle, understanding challenges and barriers that extend beyond the health system and settings, and acknowledging that its effectiveness may be compromised if these challenges are not adequately addressed.

Despite abundant literature, there are still gaps regarding the relationship between CQI and other dimensions within the healthcare system. No studies have examined the impact of CQI initiatives on catastrophic health expenditure, effective service coverage, patient-centredness, comprehensiveness, equity, health security, and responsiveness.

Limitations

In conducting this review, it has some limitations to consider. Firstly, only articles published in English were included, which may introduce the exclusion of relevant non-English articles. Additionally, as this review follows a scoping methodology, the focus is on synthesising available evidence rather than critically evaluating or scoring the quality of the included articles.

Continuous quality improvement is investigated as a continuous and ongoing intervention, where the implementation time can vary across different cycles. The CQI team and implementation timelines were critical elements of CQI in different models. Among the commonly used approaches, the PDSA or PDCA is frequently employed. In most CQI models, a wide range of tools, nineteen tools, are commonly utilized to support the improvement process. Cultural, technical, structural, and strategic barriers and facilitators are significant in implementing CQI initiatives. Implementing the CQI initiative aims to improve health system blocks, enhance health service delivery process and output, and ultimately prevent morbidity and reduce mortality. For future researchers, considering that CQI is context-dependent approach, conducting scale-up implementation research about catastrophic health expenditure, effective service coverage, patient-centredness, comprehensiveness, equity, health security, and responsiveness across various settings and health issues would be valuable.

Availability of data and materials

The data used and/or analyzed during the current study are available in this manuscript and/or the supplementary file.

Shewhart WA, Deming WE. Memoriam: Walter A. Shewhart, 1891–1967. Am Stat. 1967;21(2):39–40.

Article   Google Scholar  

Shewhart WA. Statistical method from the viewpoint of quality control. New York: Dover; 1986. ISBN 978-0486652320. OCLC 13822053. Reprint. Originally published: Washington, DC: Graduate School of the Department of Agriculture, 1939.

Moen R, editor Foundation and History of the PDSA Cycle. Asian network for quality conference Tokyo. https://www.deming.org/sites/default/files/pdf/2015/PDSA_History_Ron_MoenPdf . 2009.

Kuperman G, James B, Jacobsen J, Gardner RM. Continuous quality improvement applied to medical care: experiences at LDS hospital. Med Decis Making. 1991;11(4suppl):S60–65.

Article   CAS   PubMed   Google Scholar  

Singh J, Singh H. Continuous improvement philosophy–literature review and directions. Benchmarking: An International Journal. 2015;22(1):75–119.

Goldstone J. Presidential address: Sony, Porsche, and vascular surgery in the 21st century. J Vasc Surg. 1997;25(2):201–10.

Radawski D. Continuous quality improvement: origins, concepts, problems, and applications. J Physician Assistant Educ. 1999;10(1):12–6.

Shortell SM, O’Brien JL, Carman JM, Foster RW, Hughes E, Boerstler H, et al. Assessing the impact of continuous quality improvement/total quality management: concept versus implementation. Health Serv Res. 1995;30(2):377.

CAS   PubMed   PubMed Central   Google Scholar  

Lohr K. Quality of health care: an introduction to critical definitions, concepts, principles, and practicalities. Striving for quality in health care. 1991.

Berwick DM. The clinical process and the quality process. Qual Manage Healthc. 1992;1(1):1–8.

Article   CAS   Google Scholar  

Gift B. On the road to TQM. Food Manage. 1992;27(4):88–9.

CAS   PubMed   Google Scholar  

Greiner A, Knebel E. The core competencies needed for health care professionals. health professions education: A bridge to quality. 2003:45–73.

McCalman J, Bailie R, Bainbridge R, McPhail-Bell K, Percival N, Askew D et al. Continuous quality improvement and comprehensive primary health care: a systems framework to improve service quality and health outcomes. Front Public Health. 2018:6 (76):1–6.

Sheingold BH, Hahn JA. The history of healthcare quality: the first 100 years 1860–1960. Int J Afr Nurs Sci. 2014;1:18–22.

Google Scholar  

Donabedian A. Evaluating the quality of medical care. Milbank Q. 1966;44(3):166–206.

Institute of Medicine (US) Committee on Quality of Health Care in America. Crossing the Quality Chasm: A New Health System for the 21st Century. Washington (DC): National Academies Press (US). 2001. 2, Improving the 21st-century Health Care System. Available from: https://www.ncbi.nlm.nih.gov/books/NBK222265/ .

Rubinstein A, Barani M, Lopez AS. Quality first for effective universal health coverage in low-income and middle-income countries. Lancet Global Health. 2018;6(11):e1142–1143.

Article   PubMed   Google Scholar  

Agency for Healthcare Reserach and Quality. Quality Improvement and monitoring at your fingertips USA,: Agency for Healthcare Reserach and Quality. 2022. Available from: https://qualityindicators.ahrq.gov/ .

Anderson CA, Cassidy B, Rivenburgh P. Implementing continuous quality improvement (CQI) in hospitals: lessons learned from the International Quality Study. Qual Assur Health Care. 1991;3(3):141–6.

Gardner K, Mazza D. Quality in general practice - definitions and frameworks. Aust Fam Physician. 2012;41(3):151–4.

PubMed   Google Scholar  

Loper AC, Jensen TM, Farley AB, Morgan JD, Metz AJ. A systematic review of approaches for continuous quality improvement capacity-building. J Public Health Manage Pract. 2022;28(2):E354.

Hill JE, Stephani A-M, Sapple P, Clegg AJ. The effectiveness of continuous quality improvement for developing professional practice and improving health care outcomes: a systematic review. Implement Sci. 2020;15(1):1–14.

Candas B, Jobin G, Dubé C, Tousignant M, Abdeljelil AB, Grenier S, et al. Barriers and facilitators to implementing continuous quality improvement programs in colonoscopy services: a mixed methods systematic review. Endoscopy Int Open. 2016;4(02):E118–133.

Peters MD, Marnie C, Colquhoun H, Garritty CM, Hempel S, Horsley T, et al. Scoping reviews: reinforcing and advancing the methodology and application. Syst Reviews. 2021;10(1):1–6.

Arksey H, O’Malley L. Scoping studies: towards a methodological framework. Int J Soc Res Methodol. 2005;8(1):19–32.

Tricco AC, Lillie E, Zarin W, O’Brien KK, Colquhoun H, Levac D, et al. PRISMA extension for scoping reviews (PRISMA-ScR): checklist and explanation. Ann Intern Med. 2018;169(7):467–73.

McGowan J, Straus S, Moher D, Langlois EV, O’Brien KK, Horsley T, et al. Reporting scoping reviews—PRISMA ScR extension. J Clin Epidemiol. 2020;123:177–9.

Donabedian A. Explorations in quality assessment and monitoring: the definition of quality and approaches to its assessment. Health Administration Press, Ann Arbor. 1980;1.

World Health Organization. Operational framework for primary health care: transforming vision into action. Geneva: World Health Organization and the United Nations Children’s Fund (UNICEF); 2020 [updated 14 December 2020; cited 2023 Nov Oct 17]. Available from: https://www.who.int/publications/i/item/9789240017832 .

The Joanna Briggs Institute. The Joanna Briggs Institute Reviewers’ Manual :2014 edition. Australia: The Joanna Briggs Institute. 2014:88–91.

Rihal CS, Kamath CC, Holmes DR Jr, Reller MK, Anderson SS, McMurtry EK, et al. Economic and clinical outcomes of a physician-led continuous quality improvement intervention in the delivery of percutaneous coronary intervention. Am J Manag Care. 2006;12(8):445–52.

Ade-Oshifogun JB, Dufelmeier T. Prevention and Management of Do not return notices: a quality improvement process for Supplemental staffing nursing agencies. Nurs Forum. 2012;47(2):106–12.

Rubenstein L, Khodyakov D, Hempel S, Danz M, Salem-Schatz S, Foy R, et al. How can we recognize continuous quality improvement? Int J Qual Health Care. 2014;26(1):6–15.

O’Neill SM, Hempel S, Lim YW, Danz MS, Foy R, Suttorp MJ, et al. Identifying continuous quality improvement publications: what makes an improvement intervention ‘CQI’? BMJ Qual Saf. 2011;20(12):1011–9.

Article   PubMed   PubMed Central   Google Scholar  

Sibthorpe B, Gardner K, McAullay D. Furthering the quality agenda in Aboriginal community controlled health services: understanding the relationship between accreditation, continuous quality improvement and national key performance indicator reporting. Aust J Prim Health. 2016;22(4):270–5.

Bennett CL, Crane JM. Quality improvement efforts in oncology: are we ready to begin? Cancer Invest. 2001;19(1):86–95.

VanValkenburgh DA. Implementing continuous quality improvement at the facility level. Adv Ren Replace Ther. 2001;8(2):104–13.

Loper AC, Jensen TM, Farley AB, Morgan JD, Metz AJ. A systematic review of approaches for continuous quality improvement capacity-building. J Public Health Manage Practice. 2022;28(2):E354–361.

Ryan M. Achieving and sustaining quality in healthcare. Front Health Serv Manag. 2004;20(3):3–11.

Nicolucci A, Allotta G, Allegra G, Cordaro G, D’Agati F, Di Benedetto A, et al. Five-year impact of a continuous quality improvement effort implemented by a network of diabetes outpatient clinics. Diabetes Care. 2008;31(1):57–62.

Wakefield BJ, Blegen MA, Uden-Holman T, Vaughn T, Chrischilles E, Wakefield DS. Organizational culture, continuous quality improvement, and medication administration error reporting. Am J Med Qual. 2001;16(4):128–34.

Sori DA, Debelew GT, Degefa LS, Asefa Z. Continuous quality improvement strategy for increasing immediate postpartum long-acting reversible contraceptive use at Jimma University Medical Center, Jimma, Ethiopia. BMJ Open Qual. 2023;12(1):e002051.

Roche B, Robin C, Deleaval PJ, Marti MC. Continuous quality improvement in ambulatory surgery: the non-attending patient. Ambul Surg. 1998;6(2):97–100.

O’Connor JB, Sondhi SS, Mullen KD, McCullough AJ. A continuous quality improvement initiative reduces inappropriate prescribing of prophylactic antibiotics for endoscopic procedures. Am J Gastroenterol. 1999;94(8):2115–21.

Ursu A, Greenberg G, McKee M. Continuous quality improvement methodology: a case study on multidisciplinary collaboration to improve chlamydia screening. Fam Med Community Health. 2019;7(2):e000085.

Quick B, Nordstrom S, Johnson K. Using continuous quality improvement to implement evidence-based medicine. Lippincotts Case Manag. 2006;11(6):305–15 ( quiz 16 – 7 ).

Oyeledun B, Phillips A, Oronsaye F, Alo OD, Shaffer N, Osibo B, et al. The effect of a continuous quality improvement intervention on retention-in-care at 6 months postpartum in a PMTCT Program in Northern Nigeria: results of a cluster randomized controlled study. J Acquir Immune Defic Syndr. 2017;75(Suppl 2):S156–164.

Nyengerai T, Phohole M, Iqaba N, Kinge CW, Gori E, Moyo K, et al. Quality of service and continuous quality improvement in voluntary medical male circumcision programme across four provinces in South Africa: longitudinal and cross-sectional programme data. PLoS ONE. 2021;16(8):e0254850.

Article   CAS   PubMed   PubMed Central   Google Scholar  

Wang J, Zhang H, Liu J, Zhang K, Yi B, Liu Y, et al. Implementation of a continuous quality improvement program reduces the occurrence of peritonitis in PD. Ren Fail. 2014;36(7):1029–32.

Stikes R, Barbier D. Applying the plan-do-study-act model to increase the use of kangaroo care. J Nurs Manag. 2013;21(1):70–8.

Wagner AD, Mugo C, Bluemer-Miroite S, Mutiti PM, Wamalwa DC, Bukusi D, et al. Continuous quality improvement intervention for adolescent and young adult HIV testing services in Kenya improves HIV knowledge. AIDS. 2017;31(Suppl 3):S243–252.

Le RD, Melanson SE, Santos KS, Paredes JD, Baum JM, Goonan EM, et al. Using lean principles to optimise inpatient phlebotomy services. J Clin Pathol. 2014;67(8):724–30.

Manyazewal T, Mekonnen A, Demelew T, Mengestu S, Abdu Y, Mammo D, et al. Improving immunization capacity in Ethiopia through continuous quality improvement interventions: a prospective quasi-experimental study. Infect Dis Poverty. 2018;7:7.

Kamiya Y, Ishijma H, Hagiwara A, Takahashi S, Ngonyani HAM, Samky E. Evaluating the impact of continuous quality improvement methods at hospitals in Tanzania: a cluster-randomized trial. Int J Qual Health Care. 2017;29(1):32–9.

Kibbe DC, Bentz E, McLaughlin CP. Continuous quality improvement for continuity of care. J Fam Pract. 1993;36(3):304–8.

Adrawa N, Ongiro S, Lotee K, Seret J, Adeke M, Izudi J. Use of a context-specific package to increase sputum smear monitoring among people with pulmonary tuberculosis in Uganda: a quality improvement study. BMJ Open Qual. 2023;12(3):1–6.

Hunt P, Hunter SB, Levan D. Continuous quality improvement in substance abuse treatment facilities: how much does it cost? J Subst Abuse Treat. 2017;77:133–40.

Azadeh A, Ameli M, Alisoltani N, Motevali Haghighi S. A unique fuzzy multi-control approach for continuous quality improvement in a radio therapy department. Qual Quantity. 2016;50(6):2469–93.

Memiah P, Tlale J, Shimabale M, Nzyoka S, Komba P, Sebeza J, et al. Continuous quality improvement (CQI) institutionalization to reach 95:95:95 HIV targets: a multicountry experience from the Global South. BMC Health Serv Res. 2021;21(1):711.

Yapa HM, De Neve JW, Chetty T, Herbst C, Post FA, Jiamsakul A, et al. The impact of continuous quality improvement on coverage of antenatal HIV care tests in rural South Africa: results of a stepped-wedge cluster-randomised controlled implementation trial. PLoS Med. 2020;17(10):e1003150.

Dadi TL, Abebo TA, Yeshitla A, Abera Y, Tadesse D, Tsegaye S, et al. Impact of quality improvement interventions on facility readiness, quality and uptake of maternal and child health services in developing regions of Ethiopia: a secondary analysis of programme data. BMJ Open Qual. 2023;12(4):e002140.

Weinberg M, Fuentes JM, Ruiz AI, Lozano FW, Angel E, Gaitan H, et al. Reducing infections among women undergoing cesarean section in Colombia by means of continuous quality improvement methods. Arch Intern Med. 2001;161(19):2357–65.

Andreoni V, Bilak Y, Bukumira M, Halfer D, Lynch-Stapleton P, Perez C. Project management: putting continuous quality improvement theory into practice. J Nurs Care Qual. 1995;9(3):29–37.

Balfour ME, Zinn TE, Cason K, Fox J, Morales M, Berdeja C, et al. Provider-payer partnerships as an engine for continuous quality improvement. Psychiatric Serv. 2018;69(6):623–5.

Agurto I, Sandoval J, De La Rosa M, Guardado ME. Improving cervical cancer prevention in a developing country. Int J Qual Health Care. 2006;18(2):81–6.

Anderson CI, Basson MD, Ali M, Davis AT, Osmer RL, McLeod MK, et al. Comprehensive multicenter graduate surgical education initiative incorporating entrustable professional activities, continuous quality improvement cycles, and a web-based platform to enhance teaching and learning. J Am Coll Surg. 2018;227(1):64–76.

Benjamin S, Seaman M. Applying continuous quality improvement and human performance technology to primary health care in Bahrain. Health Care Superv. 1998;17(1):62–71.

Byabagambi J, Marks P, Megere H, Karamagi E, Byakika S, Opio A, et al. Improving the quality of voluntary medical male circumcision through use of the continuous quality improvement approach: a pilot in 30 PEPFAR-Supported sites in Uganda. PLoS ONE. 2015;10(7):e0133369.

Hogg S, Roe Y, Mills R. Implementing evidence-based continuous quality improvement strategies in an urban Aboriginal Community Controlled Health Service in South East Queensland: a best practice implementation pilot. JBI Database Syst Rev Implement Rep. 2017;15(1):178–87.

Hopper MB, Morgan S. Continuous quality improvement initiative for pressure ulcer prevention. J Wound Ostomy Cont Nurs. 2014;41(2):178–80.

Ji J, Jiang DD, Xu Z, Yang YQ, Qian KY, Zhang MX. Continuous quality improvement of nutrition management during radiotherapy in patients with nasopharyngeal carcinoma. Nurs Open. 2021;8(6):3261–70.

Chen M, Deng JH, Zhou FD, Wang M, Wang HY. Improving the management of anemia in hemodialysis patients by implementing the continuous quality improvement program. Blood Purif. 2006;24(3):282–6.

Reeves S, Matney K, Crane V. Continuous quality improvement as an ideal in hospital practice. Health Care Superv. 1995;13(4):1–12.

Barton AJ, Danek G, Johns P, Coons M. Improving patient outcomes through CQI: vascular access planning. J Nurs Care Qual. 1998;13(2):77–85.

Buttigieg SC, Gauci D, Dey P. Continuous quality improvement in a Maltese hospital using logical framework analysis. J Health Organ Manag. 2016;30(7):1026–46.

Take N, Byakika S, Tasei H, Yoshikawa T. The effect of 5S-continuous quality improvement-total quality management approach on staff motivation, patients’ waiting time and patient satisfaction with services at hospitals in Uganda. J Public Health Afr. 2015;6(1):486.

PubMed   PubMed Central   Google Scholar  

Jacobson GH, McCoin NS, Lescallette R, Russ S, Slovis CM. Kaizen: a method of process improvement in the emergency department. Acad Emerg Med. 2009;16(12):1341–9.

Agarwal S, Gallo J, Parashar A, Agarwal K, Ellis S, Khot U, et al. Impact of lean six sigma process improvement methodology on cardiac catheterization laboratory efficiency. Catheter Cardiovasc Interv. 2015;85:S119.

Rahul G, Samanta AK, Varaprasad G A Lean Six Sigma approach to reduce overcrowding of patients and improving the discharge process in a super-specialty hospital. In 2020 International Conference on System, Computation, Automation and Networking (ICSCAN) 2020 July 3 (pp. 1-6). IEEE

Patel J, Nattabi B, Long R, Durey A, Naoum S, Kruger E, et al. The 5 C model: A proposed continuous quality improvement framework for volunteer dental services in remote Australian Aboriginal communities. Community Dent Oral Epidemiol. 2023;51(6):1150–8.

Van Acker B, McIntosh G, Gudes M. Continuous quality improvement techniques enhance HMO members’ immunization rates. J Healthc Qual. 1998;20(2):36–41.

Horine PD, Pohjala ED, Luecke RW. Healthcare financial managers and CQI. Healthc Financ Manage. 1993;47(9):34.

Reynolds JL. Reducing the frequency of episiotomies through a continuous quality improvement program. CMAJ. 1995;153(3):275–82.

Bunik M, Galloway K, Maughlin M, Hyman D. First five quality improvement program increases adherence and continuity with well-child care. Pediatr Qual Saf. 2021;6(6):e484.

Boyle TA, MacKinnon NJ, Mahaffey T, Duggan K, Dow N. Challenges of standardized continuous quality improvement programs in community pharmacies: the case of SafetyNET-Rx. Res Social Adm Pharm. 2012;8(6):499–508.

Price A, Schwartz R, Cohen J, Manson H, Scott F. Assessing continuous quality improvement in public health: adapting lessons from healthcare. Healthc Policy. 2017;12(3):34–49.

Gage AD, Gotsadze T, Seid E, Mutasa R, Friedman J. The influence of continuous quality improvement on healthcare quality: a mixed-methods study from Zimbabwe. Soc Sci Med. 2022;298:114831.

Chan YC, Ho SJ. Continuous quality improvement: a survey of American and Canadian healthcare executives. Hosp Health Serv Adm. 1997;42(4):525–44.

Balas EA, Puryear J, Mitchell JA, Barter B. How to structure clinical practice guidelines for continuous quality improvement? J Med Syst. 1994;18(5):289–97.

ElChamaa R, Seely AJE, Jeong D, Kitto S. Barriers and facilitators to the implementation and adoption of a continuous quality improvement program in surgery: a case study. J Contin Educ Health Prof. 2022;42(4):227–35.

Candas B, Jobin G, Dubé C, Tousignant M, Abdeljelil A, Grenier S, et al. Barriers and facilitators to implementing continuous quality improvement programs in colonoscopy services: a mixed methods systematic review. Endoscopy Int Open. 2016;4(2):E118–133.

Brandrud AS, Schreiner A, Hjortdahl P, Helljesen GS, Nyen B, Nelson EC. Three success factors for continual improvement in healthcare: an analysis of the reports of improvement team members. BMJ Qual Saf. 2011;20(3):251–9.

Lee S, Choi KS, Kang HY, Cho W, Chae YM. Assessing the factors influencing continuous quality improvement implementation: experience in Korean hospitals. Int J Qual Health Care. 2002;14(5):383–91.

Horwood C, Butler L, Barker P, Phakathi S, Haskins L, Grant M, et al. A continuous quality improvement intervention to improve the effectiveness of community health workers providing care to mothers and children: a cluster randomised controlled trial in South Africa. Hum Resour Health. 2017;15(1):39.

Hyrkäs K, Lehti K. Continuous quality improvement through team supervision supported by continuous self-monitoring of work and systematic patient feedback. J Nurs Manag. 2003;11(3):177–88.

Akdemir N, Peterson LN, Campbell CM, Scheele F. Evaluation of continuous quality improvement in accreditation for medical education. BMC Med Educ. 2020;20(Suppl 1):308.

Barzansky B, Hunt D, Moineau G, Ahn D, Lai CW, Humphrey H, et al. Continuous quality improvement in an accreditation system for undergraduate medical education: benefits and challenges. Med Teach. 2015;37(11):1032–8.

Gaylis F, Nasseri R, Salmasi A, Anderson C, Mohedin S, Prime R, et al. Implementing continuous quality improvement in an integrated community urology practice: lessons learned. Urology. 2021;153:139–46.

Gaga S, Mqoqi N, Chimatira R, Moko S, Igumbor JO. Continuous quality improvement in HIV and TB services at selected healthcare facilities in South Africa. South Afr J HIV Med. 2021;22(1):1202.

Wang F, Yao D. Application effect of continuous quality improvement measures on patient satisfaction and quality of life in gynecological nursing. Am J Transl Res. 2021;13(6):6391–8.

Lee SB, Lee LL, Yeung RS, Chan J. A continuous quality improvement project to reduce medication error in the emergency department. World J Emerg Med. 2013;4(3):179–82.

Chiang AA, Lee KC, Lee JC, Wei CH. Effectiveness of a continuous quality improvement program aiming to reduce unplanned extubation: a prospective study. Intensive Care Med. 1996;22(11):1269–71.

Chinnaiyan K, Al-Mallah M, Goraya T, Patel S, Kazerooni E, Poopat C, et al. Impact of a continuous quality improvement initiative on appropriate use of coronary CT angiography: results from a multicenter, statewide registry, the advanced cardiovascular imaging consortium (ACIC). J Cardiovasc Comput Tomogr. 2011;5(4):S29–30.

Gibson-Helm M, Rumbold A, Teede H, Ranasinha S, Bailie R, Boyle J. A continuous quality improvement initiative: improving the provision of pregnancy care for Aboriginal and Torres Strait Islander women. BJOG: Int J Obstet Gynecol. 2015;122:400–1.

Bennett IM, Coco A, Anderson J, Horst M, Gambler AS, Barr WB, et al. Improving maternal care with a continuous quality improvement strategy: a report from the interventions to minimize preterm and low birth weight infants through continuous improvement techniques (IMPLICIT) network. J Am Board Fam Med. 2009;22(4):380–6.

Krall SP, Iv CLR, Donahue L. Effect of continuous quality improvement methods on reducing triage to thrombolytic interval for Acute myocardial infarction. Acad Emerg Med. 1995;2(7):603–9.

Swanson TK, Eilers GM. Physician and staff acceptance of continuous quality improvement. Fam Med. 1994;26(9):583–6.

Yu Y, Zhou Y, Wang H, Zhou T, Li Q, Li T, et al. Impact of continuous quality improvement initiatives on clinical outcomes in peritoneal dialysis. Perit Dial Int. 2014;34(Suppl 2):S43–48.

Schiff GD, Goldfield NI. Deming meets Braverman: toward a progressive analysis of the continuous quality improvement paradigm. Int J Health Serv. 1994;24(4):655–73.

American Hospital Association Division of Quality Resources Chicago, IL: The role of hospital leadership in the continuous improvement of patient care quality. American Hospital Association. J Healthc Qual. 1992;14(5):8–14,22.

Scriven M. The Logic and Methodology of checklists [dissertation]. Western Michigan University; 2000.

Hales B, Terblanche M, Fowler R, Sibbald W. Development of medical checklists for improved quality of patient care. Int J Qual Health Care. 2008;20(1):22–30.

Vermeir P, Vandijck D, Degroote S, Peleman R, Verhaeghe R, Mortier E, et al. Communication in healthcare: a narrative review of the literature and practical recommendations. Int J Clin Pract. 2015;69(11):1257–67.

Eljiz K, Greenfield D, Hogden A, Taylor R, Siddiqui N, Agaliotis M, et al. Improving knowledge translation for increased engagement and impact in healthcare. BMJ open Qual. 2020;9(3):e000983.

O’Brien JL, Shortell SM, Hughes EF, Foster RW, Carman JM, Boerstler H, et al. An integrative model for organization-wide quality improvement: lessons from the field. Qual Manage Healthc. 1995;3(4):19–30.

Adily A, Girgis S, D’Este C, Matthews V, Ward JE. Syphilis testing performance in Aboriginal primary health care: exploring impact of continuous quality improvement over time. Aust J Prim Health. 2020;26(2):178–83.

Horwood C, Butler L, Barker P, Phakathi S, Haskins L, Grant M, et al. A continuous quality improvement intervention to improve the effectiveness of community health workers providing care to mothers and children: a cluster randomised controlled trial in South Africa. Hum Resour Health. 2017;15:1–11.

Veillard J, Cowling K, Bitton A, Ratcliffe H, Kimball M, Barkley S, et al. Better measurement for performance improvement in low- and middle-income countries: the primary Health Care Performance Initiative (PHCPI) experience of conceptual framework development and indicator selection. Milbank Q. 2017;95(4):836–83.

Barbazza E, Kringos D, Kruse I, Klazinga NS, Tello JE. Creating performance intelligence for primary health care strengthening in Europe. BMC Health Serv Res. 2019;19(1):1006.

Assefa Y, Hill PS, Gilks CF, Admassu M, Tesfaye D, Van Damme W. Primary health care contributions to universal health coverage. Ethiopia Bull World Health Organ. 2020;98(12):894.

Van Weel C, Kidd MR. Why strengthening primary health care is essential to achieving universal health coverage. CMAJ. 2018;190(15):E463–466.

Download references

Acknowledgements

Not applicable.

The authors received no fund.

Author information

Authors and affiliations.

School of Public Health, The University of Queensland, Brisbane, Australia

Aklilu Endalamaw, Resham B Khatri, Tesfaye Setegn Mengistu, Daniel Erku & Yibeltal Assefa

College of Medicine and Health Sciences, Bahir Dar University, Bahir Dar, Ethiopia

Aklilu Endalamaw & Tesfaye Setegn Mengistu

Health Social Science and Development Research Institute, Kathmandu, Nepal

Resham B Khatri

Centre for Applied Health Economics, School of Medicine, Grifth University, Brisbane, Australia

Daniel Erku

Menzies Health Institute Queensland, Grifth University, Brisbane, Australia

International Institute for Primary Health Care in Ethiopia, Addis Ababa, Ethiopia

Eskinder Wolka & Anteneh Zewdie

You can also search for this author in PubMed   Google Scholar

Contributions

AE conceptualized the study, developed the first draft of the manuscript, and managing feedbacks from co-authors. YA conceptualized the study, provided feedback, and supervised the whole processes. RBK provided feedback throughout. TSM provided feedback throughout. DE provided feedback throughout. EW provided feedback throughout. AZ provided feedback throughout. All authors read and approved the final manuscript.

Corresponding author

Correspondence to Aklilu Endalamaw .

Ethics declarations

Ethics approval and consent to participate.

Not applicable because this research is based on publicly available articles.

Consent for publication

Competing interests.

The authors declare that they have no competing interests.

Additional information

Publisher’s note.

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary Information

Supplementary material 1., supplementary material 2., rights and permissions.

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ . The Creative Commons Public Domain Dedication waiver ( http://creativecommons.org/publicdomain/zero/1.0/ ) applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Reprints and permissions

About this article

Cite this article.

Endalamaw, A., Khatri, R.B., Mengistu, T.S. et al. A scoping review of continuous quality improvement in healthcare system: conceptualization, models and tools, barriers and facilitators, and impact. BMC Health Serv Res 24 , 487 (2024). https://doi.org/10.1186/s12913-024-10828-0

Download citation

Received : 27 December 2023

Accepted : 05 March 2024

Published : 19 April 2024

DOI : https://doi.org/10.1186/s12913-024-10828-0

Share this article

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

• Continuous quality improvement
• Quality of Care

BMC Health Services Research

ISSN: 1472-6963

• General enquiries: [email protected]

Ileorectal anastomosis in ulcerative colitis: what do surgeons and patients need to know? A systematic literature review

Affiliations.

• 1 University Hospitals Bristol and Weston NHS Foundation Trust, UK.
• 2 Somerset NHS Foundation Trust, UK.
• PMID: 38660816
• DOI: 10.1308/rcsann.2024.0012

Introduction: Ileal pouch-anal anastomosis (IPAA) is currently the gold standard for restoration of gastrointestinal continuity after colectomy for ulcerative colitis in the UK. However, with further experience of the risks relating to IPAA, the use of ileorectal anastomosis (IRA) is being revisited. Decisions regarding restorative surgery after colectomy are individual to every patient's circumstances, and this paper aims to provide a comprehensive review of the literature to guide a full discussion of the risks and benefits of IRA.

Methods: A systematic literature review was conducted of papers published from 2000 onwards relating to IRA and ulcerative colitis, in accordance with the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines. The papers were reviewed by two independent surgeons for information it was felt that patients and surgeons would want to know about the operation (cancer risk, bowel function, sexual and urinary function, fecundity/fertility and postoperative complications).

Results: Seventeen papers were identified for inclusion as they reported original data on one or more of the categories identified for discussion. The median ten-year cancer risk after IRA was 2.8% and the median failure rate at ten years was 21%. IRA was generally found to have lower postoperative complication rates and better bowel function than IRA, with sexual function similar and fecundity not commented on in any paper.

Conclusions: For some patients, IRA can offer restorative surgery in the short or long term, with acceptable cancer risk, failure rate and postoperative complications, while avoiding the higher risks associated with IPAA.

Keywords: ileorectal anastomosis; ulcerative colitis.

Publication types