Cited by 464Meta-analysis and systematic reviewsClinical practice guidelines implementationDelphi Technique in Research

Strengthening systematic reviews in public health: guidance in the Cochrane Handbook for Systematic Reviews of Interventions , 2nd edition

Open access
Cumpston, Miranda S, McKenzie, Joanne E, Welch, Vivian A, Brennan, Sue E·2022·Journal of Public Health

Abstract

Aims: Decision makers in public health practice and policy rely on access to trustworthy, relevant, synthesized evidence. The second edition of the Cochrane Handbook for Systematic Reviews of Interventions (‘the Handbook’) reflects a major revision in guidance for authors of systematic reviews, incorporating a decade of methodological development and a number of significant changes to previous recommendations. This paper aims to highlight new guidance that addresses a number of key methodological challenges for authors of systematic reviews in public health. Results: The revised Handbook includes guidance on framing public health research questions for synthesis, considering equity, intervention complexity, risk of bias assessment and synthesis methods other than meta-analysis. Reviews of public health interventions frequently encounter the types of methodological complexity addressed in this new guidance. Conclusion: We hope that readers will find that the Cochrane Handbook includes detailed and thoughtful guidance on both conceptualizing and executing systematic reviews relevant to public health questions. Considering the available methods guidance will, we hope, provide support for authors of public health reviews to tackle the challenges they encounter, strengthen their analysis and provide useful answers to the important questions asked by stakeholders and users of public health evidence.

AI snapshot

Written from the paper’s full text.

TL;DR

This paper is a narrative overview of new and revised methodological guidance in the second edition of the Cochrane Handbook for Systematic Reviews of Interventions, aimed at authors of public health systematic reviews. It highlights Handbook guidance on framing review questions, equity, intervention complexity, risk of bias across diverse study designs, and synthesis methods other than meta-analysis.

Key findings

  • The second edition of the Handbook represents a major revision incorporating a decade of methodological development, with new standalone guidance on equity (Chapter 16) and, for the first time, alternative statistical synthesis methods (Chapter 12).
  • Reviews of public health interventions frequently encounter the methodological complexity addressed by this guidance, including interventions that vary in theoretical approach, components and implementation, and populations that differ in important ways.
  • Around a third to half of all systematic reviews do not use meta-analysis at all, and more do not use meta-analysis for all outcomes (citing refs 23–24).
  • Alternative synthesis methods presented in Chapter 12 include summary statistics describing the range of effect estimates, vote counting based on direction of effect, and combining P values, with companion visual displays such as box plots, harvest plots and albatross plots; these yield results "more limited for decision making in comparison to meta-analysis."

Methods

  • Design: a narrative guidance/commentary paper highlighting selected areas of updated Cochrane guidance of particular relevance to public health reviews; it is not itself a systematic review.
  • Data: no new data were generated or analysed (per the paper's data availability statement); illustrative examples are drawn from existing reviews (e.g. a school-based physical activity review and a rotavirus vaccine review).
  • Content covers Handbook chapters on scope and eligibility (Chapters 2–3), equity (Chapter 16), intervention complexity (Chapter 17), bias (Chapters 7, 13), risk-of-bias tools RoB 2 (Chapter 8) and ROBINS-I (Chapter 25), and alternative synthesis (Chapter 12), plus PRISMA 2020 and SWiM reporting guidelines.

Limitations

  • The paper states no formal limitations section; it is explicitly a selective highlight of "some areas" of updated guidance rather than a comprehensive account.
  • Evident from the text: as a narrative overview without new data or empirical evaluation, it does not assess the uptake, impact or effectiveness of the guidance it describes, and its recommendations rest on the Handbook's methodological development rather than on primary research conducted here.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1093/pubmed/fdac036

Cites

19 of 19 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 24 cited sources checked · 0 supported · 0 flagged

    • Classified as probably not a substantial claim. 21
    • May combine two claims. 11
    • Probably not a substantial claim: may not pass S2 (checkable), S4 (based).

      Interpretationreasoning

      Reviews of public health interventions frequently encounter the types of methodological complexity addressed in this new guidance.

      “Reviews of public health interventions frequently encounter the types of methodological complexity addressed in this new guidance.”
      Quote in the paperNot a substantial claim
      • Rests on an assumption: It is common for reviews in public health to consider interventions that vary in theoretical approach, components and implementation among the included studies.
      • Rests on an assumption: It is well known that public health interventions are often comprised of multiple components (what may be considered ‘complicated’ interventions).
    • Probably not a substantial claim: may not pass S3 (load-bearing).

      Premisenone given

      Additional complexity in interventions may also arise from interactions, between components, between interventions and participants, or with the context in which the intervention occurs.

      “Additional complexity in interventions may also arise from interactions, between components, between interventions and participants, or with the context in which the intervention occurs.”
      Quote in the paperNot a substantial claim
      • Rests on an assumption: It is well known that public health interventions are often comprised of multiple components (what may be considered ‘complicated’ interventions).
    • Probably not a substantial claim: may not pass S3 (load-bearing).

      Premisecitation

      Addressed for the first time in a standalone chapter, Chapter 16 of the Handbook presents strategies to consider and incorporate equity throughout the systematic review process.

      “Addressed for the first time in a standalone chapter, Chapter 16 of the Handbook presents strategies to consider and incorporate equity throughout the systematic review process.13”
      Quote in the paperNot a substantial claim0 of 1 sources checked
      • cites [13] Welch

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      Interpretationcitation

      Recent examples of collaboration during the COVID-19 crisis, such as that between Cochrane, WHO and other policy agencies, highlight the potential impact of well-conducted systematic reviews that meet the needs of policy partners.

      “Recent examples of collaboration during the COVID-19 crisis, such as that between Cochrane, WHO and other policy agencies, highlight the potential impact of well-conducted systematic reviews that meet the needs of policy partners.4”
      Quote in the paperNot a substantial claim0 of 1 sources checked
      • cites [4] Cochrane, 2021

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    • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

      Premisecitation

      Chapter 7 of the updated Handbook outlines the theoretical underpinnings of bias, using evidence-based methods to identify risk factors associated with bias in results and discussing the role of conflict of interest.

      “Chapter 7 of the updated Handbook outlines the theoretical underpinnings of bias, using evidence-based methods to identify risk factors associated with bias in results and discussing the role of conflict of interest.17”
      Quote in the paperNot a substantial claim0 of 1 sources checked
      • cites [17] Boutron, 2019

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    • Classified as probably not a substantial claim. May combine two claims.

      Premisecitation

      The revised Handbook includes guidance on framing public health research questions for synthesis, considering equity, intervention complexity, risk of bias assessment and synthesis methods other than meta-analysis.

      “The revised Handbook includes guidance on framing public health research questions for synthesis, considering equity, intervention complexity, risk of bias assessment and synthesis methods other than meta-analysis.”
      Quote in the paperSubstantial claim0 of 1 sources checked
      • cites [6] Higgins, 2019 source

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      Premisecitation

      Logic models and conceptual frameworks may help to think through the important concepts within the review.

      “Logic models and conceptual frameworks may help to think through the important concepts within the review.7”
      Quote in the paperNot a substantial claim0 of 1 sources checked
      • cites [7] Thomas, 2019

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    • Classified as probably not a substantial claim. May combine two claims.

      Premisecitation

      The second edition of the Cochrane Handbook represents a major revision of methodological guidance for authors of systematic reviews, reflecting a decade of methodological development and including a number of significant changes to previous recommendations.

      “The second edition of the Cochrane Handbook for Systematic Reviews of Interventions (‘the Handbook’) reflects a major revision in guidance for authors of systematic reviews, incorporating a decade of methodological development and a number of significant changes to previous recommendations.”
      • Also stated in: § Introduction · plain
        “Updated at the end of 2019, the second edition of the Handbook6 represents a major revision of methodological guidance for authors of systematic reviews, reflecting a decade of methodological development and including a number of significant changes to previous recommendations.”
      Quote in the paperSubstantial claim0 of 1 sources checked
      • cites [6] Higgins, 2019 source

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    • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing), S4 (based). May combine two claims.

      Interpretationnone given

      Although not every variation can be predicted in advance, the fact that variation will be found is predictable.

      “Although not every variation can be predicted in advance, the fact that variation will be found is predictable.”
      Quote in the paperNot a substantial claim
      • Rests on an assumption: It is common for reviews in public health to consider interventions that vary in theoretical approach, components and implementation among the included studies.
    • Probably not a substantial claim: may not pass S3 (load-bearing).

      Premisecitation

      Undertaking a review with a systems perspective takes the consideration of complexity even further, considering an intervention as an event within a broader, adaptive system.

      “Undertaking a review with a systems perspective takes the consideration of complexity even further, considering an intervention as an event within a broader, adaptive system.15”
      Quote in the paperNot a substantial claim0 of 1 sources checked
      • cites [15] Thomas, 2019

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    • Classified as probably not a substantial claim. May combine two claims.

      Premisecitation

      Systematic reviews are widely published on public health topics and routinely incorporated into guidelines.

      “Systematic reviews are widely published on public health topics and routinely incorporated into guidelines.1–3”
      Quote in the paperSubstantial claim0 of 3 sources checked
      • cites [1] World Health Organization, 2018

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      • cites [2] NICE, 2020

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      • cites [3] National Health and Medical Research Council, 2021

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    • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

      Premisecitation

      The Cochrane Handbook incorporates practical guidance on conducting a systematic review from idea to publication and has been internationally recognized as a gold standard resource since its first print publication in 2008.

      “The Cochrane Handbook for Systematic Reviews of Interventions (‘the Handbook’) incorporates practical guidance on conducting a systematic review from idea to publication and has been internationally recognized as a gold standard resource since its first print publication in 2008.5”
      Quote in the paperNot a substantial claim0 of 1 sources checked
      • cites [5] Higgins, 2008 source

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    • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

      Premisecitation

      Chapter 25 details the Risk of Bias in Non-Randomized Studies of Interventions tool (ROBINS-I), which is designed to be applied to a wide range of study designs, including follow-up (cohort) studies, and controlled or uncontrolled before-after studies (including interrupted time series).

      “Chapter 25 details the Risk of Bias in Non-Randomized Studies of Interventions tool (ROBINS-I), which is designed to be applied to a wide range of study designs, including follow-up (cohort) studies, and controlled or uncontrolled before–after studies (including interrupted time series).20”
      Quote in the paperNot a substantial claim0 of 1 sources checked
      • cites [20] Sterne, 2019

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    • Classified as probably not a substantial claim.

      Premisecitation

      Guidance in the updated Handbook suggests that authors specify how population or intervention groups will be used in specific syntheses or comparisons within the review, in enough detail that the selection of studies for inclusion in a group or synthesis could be replicated.

      “Guidance in the updated Handbook suggests that authors then specify how these groups will be used in specific syntheses or comparisons within the review, in enough detail that the selection of studies for inclusion in a group or synthesis could be replicated.8”
      Quote in the paperSubstantial claim0 of 1 sources checked
      • cites [8] McKenzie, 2019

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    • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

      Premisecitation

      For the first time, Chapter 12 of the Handbook presents a number of alternative statistical synthesis methods for this scenario, including the use of summary statistics to describe the observed range of intervention effect estimates, vote counting based on the direction of effect, or combining P values.

      “For the first time, Chapter 12 of the Handbook presents a number of alternative statistical synthesis methods for this scenario, including the use of summary statistics to describe the observed range of intervention effect estimates, vote counting based on the direction of effect, or combining P values.”
      Quote in the paperNot a substantial claim0 of 1 sources checked
      • cites [25] McKenzie, 2019

        Not checked in the free run.

      • Rests on an assumption: Reasons why meta-analysis may not be possible are varied, but one reason may be when the included primary studies do not provide the necessary data required for a meta-analysis.
    • Probably not a substantial claim: may not pass S3 (load-bearing).

      Premisecitation

      Companion visual displays for these synthesis methods are also described in the Handbook, including box plots, harvest plots and albatross plots.

      “Companion visual displays for these synthesis methods are also described, including box plots, harvest plots and albatross plots.”
      Quote in the paperNot a substantial claim0 of 1 sources checked
      • cites [25] McKenzie, 2019

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      Premisecitation

      Both tools provide structured signalling questions to assist authors in thinking through each aspect to be considered as part of the assessment process.

      “Both tools provide structured signalling questions to assist authors in thinking through each aspect to be considered as part of the assessment process.”
      Quote in the paperNot a substantial claim0 of 2 sources checked
      • cites [19] Higgins, 2019 source

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      • cites [20] Sterne, 2019

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    • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

      Premisecitation

      Chapter 17 of the Handbook outlines in further detail how authors of systematic reviews can think through what kinds of complexity might apply to their review at the planning stages, and how they might address it in the most useful way.

      “Chapter 17 of the Handbook outlines in further detail how authors of systematic reviews can think through what kinds of complexity might apply to their review at the planning stages, and how they might address it in the most useful way.15”
      Quote in the paperNot a substantial claim0 of 1 sources checked
      • cites [15] Thomas, 2019

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    • Probably not a substantial claim: may not pass S3 (load-bearing).

      Premisecitation

      Chapters 2 and 3 of the Handbook provide practical guidance on a structured approach for thinking through the scope and eligibility for the review as well as possible groupings of population, intervention, outcomes and study designs.

      “Chapters 2 and 3 of the Handbook provide practical guidance on a structured approach for thinking through the scope and eligibility for the review as well as possible groupings of population, intervention, outcomes and study designs.7,8”
      Quote in the paperNot a substantial claim0 of 2 sources checked
      • cites [7] Thomas, 2019

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      • cites [8] McKenzie, 2019

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    • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

      Premisecitation

      Chapter 8 details version 2 of the Cochrane Risk of Bias tool for randomized trials (RoB 2), which incorporates considerably updated thinking about factors important to bias, including updated guidance on cluster randomized trials, such as those where schools, families or communities are randomized to receive different interventions.

      “Chapter 8 details version 2 of the Cochrane Risk of Bias tool for randomized trials (RoB 2), which incorporates considerably updated thinking about factors important to bias, including updated guidance on cluster randomized trials, such as those where schools, families or communities are randomized to receive different interventions.19”
      Quote in the paperNot a substantial claim0 of 1 sources checked
      • cites [19] Higgins, 2019 source

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    • Probably not a substantial claim: may not pass S3 (load-bearing).

      Premisecitation

      Chapter 13 presents guidance on the risks of bias due to missing results (such as unpublished studies or unreported outcomes).

      “Chapter 13 presents guidance on the risks of bias due to missing results (such as unpublished studies or unreported outcomes).18”
      Quote in the paperNot a substantial claim0 of 1 sources checked
      • cites [18] Page, 2019

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    • May combine two claims.

      Premisecitation

      Around a third to half of all systematic reviews do not use meta-analysis at all, and more do not use meta-analysis for all outcomes.

      “Around a third to half of all systematic reviews do not use meta-analysis at all,23,24 and more do not use meta-analysis for all outcomes.”
      Quote in the paperSubstantial claim0 of 2 sources checked
      • cites [23] Campbell, 2019, Lack of transparency in reporting narrative synthesis of quantitative data: a methodological assessment of systematic reviews, J Clin Epidemiol source

        Not checked in the free run.

      • cites [24] Page, 2016, Epidemiology and reporting characteristics of systematic reviews of biomedical research: a cross-sectional study, PLoS Med source

        Not checked in the free run.

    22 of 22
    • The paper relies on this without support.

      It is common for reviews in public health to consider interventions that vary in theoretical approach, components and implementation among the included studies.

      “It is common for reviews in public health to consider interventions that vary in theoretical approach, components and implementation among the included studies.”
    • The paper relies on this without support.

      Planning for complexity can minimize bias arising from post hoc selection while improving clarity for readers.

      “Planning for complexity can minimize bias arising from post hoc selection while improving clarity for readers.”
    • The paper relies on this without support.

      Presenting a clear definition of each group and a rationale for the groups chosen enables transparency and replicability of the decisions to group studies in particular ways and enhances understanding for readers and end users of the review’s findings.

      “Presenting a clear definition of each group and a rationale for the groups chosen enables transparency and replicability of the decisions to group studies in particular ways and enhances understanding for readers and end users of the review’s findings.”
    • The paper relies on this without support.

      Considering equity explicitly in systematic reviews from question formulation to interpretation adds value to the review’s findings, enabling end users to understand whether and how the findings of the review apply to different populations and settings, and ensuring that high-level, aggregated results do not obscure important differences in effects.

      “Considering equity explicitly in systematic reviews from question formulation to interpretation adds value to the review’s findings, enabling end users to understand whether and how the findings of the review apply to different populations and settings, and ensuring that high-level, aggregated results do not obscure important differences in effects.”
    • The paper relies on this without support.

      It is well known that public health interventions are often comprised of multiple components (what may be considered ‘complicated’ interventions).

      “It is well known that public health interventions are often comprised of multiple components (what may be considered ‘complicated’ interventions).”
    • The paper relies on this without support.

      Exhaustively listing intervention components may complicate analysis without adding meaningful understanding to the review’s findings.

      “Exhaustively listing intervention components may complicate analysis without adding meaningful understanding to the review’s findings.”
    • The paper relies on this without support.

      It may be that the most useful review would not aim to estimate a universal effect, but to explore why and how an intervention may have been successful in specific cases.

      “It may be that the most useful review would not aim to estimate a universal effect, but to explore why and how an intervention may have been successful in specific cases.”
    • The paper relies on this without support.

      Although many systematic reviews of public health interventions include randomized trials, there are others that cannot, where randomized trials may be unethical, infeasible, unaffordable or simply do not exist.

      “Although many systematic reviews of public health interventions include randomized trials, there are others that cannot, where randomized trials may be unethical, infeasible, unaffordable or simply do not exist.”
    • The paper relies on this without support.

      Reasons why meta-analysis may not be possible are varied, but one reason may be when the included primary studies do not provide the necessary data required for a meta-analysis.

      “Reasons why meta-analysis may not be possible are varied, but one reason may be when the included primary studies do not provide the necessary data required for a meta-analysis.”
    • The paper relies on this without support.

      In some cases, synthesis may be inappropriate, for example where the included studies are at a high risk of bias or there are concerns about missing evidence.

      “In some cases, synthesis may be inappropriate, for example where the included studies are at a high risk of bias or there are concerns about missing evidence.”
    • The paper relies on this without support.

      Although these alternative synthesis methods yield results that are more limited for decision making in comparison to meta-analysis, they provide additional options for review authors when the required data for meta-analysis are not available.

      “Although these alternative synthesis methods yield results that are more limited for decision making in comparison to meta-analysis, they provide additional options for review authors when the required data for meta-analysis are not available.”
    • The paper relies on this without support.

      These methods may enable authors to make the most of the available data and provide a structured approach where authors may have felt limited to text-based descriptions of the findings of individual studies, which can become rapidly unwieldy where large numbers of studies or complex interventions are involved.

      “These methods may enable authors to make the most of the available data and provide a structured approach where authors may have felt limited to text-based descriptions of the findings of individual studies, which can become rapidly unwieldy where large numbers of studies or complex interventions are involved.”
    12 of 12

    Claims other papers make about this one

    Each is checked against this paper’s own text: does it say what the citing paper says it does?

    • Cochrane Collaboration guidelines require a minimum of ten studies to execute a moderator analysis.

      “According to Cochrane Collaboration guidelines (Cumpston et al. 2022), a minimum of ten studies is required to execute a moderator analysis”

      From Examining Working Memory Training for Healthy Adults—A Second-Order Meta-Analysis (2024) · cites this paper as Cumpston et al. 2022

      The 'Synthesis methods other than meta-analysis' section discusses alternatives when meta-analysis is not possible, but gives no minimum study count for moderator analysis. Searches for 'minimum of ten studies moderator analysis' and 'meta-regression subgroup analysis 10 studies minimum' found no passage establishing the claimed requirement. Page numbers were unavailable in our copy. (LLM, conf=0.75)

      Experimental — accuracy not yet measured

    Cites

    Flagged first, then by citations

    5 of the 24 references couldn’t be matched to a known paper.

    Research works printed but not linked: 12

    1. World Health Organization, 2018, WHO Handbook for Guideline Development
    2. NICE, 2020, Developing NICE Guidelines: The Manual
    3. National Health and Medical Research Council, 2021, Guidelines for Guidelines Manual
    4. Cochrane, 2021, Cochrane COVID reviews
    5. McKenzie, 2019, Cochrane Handbook for Systematic Reviews of Interventions
    6. Welch, Cochrane Handbook for Systematic Reviews of Interventions
    7. Thomas, 2019, Cochrane Handbook for Systematic Reviews of Interventions
    8. Boutron, 2019, Cochrane Handbook for Systematic Reviews of Interventions
    9. Page, 2019, Cochrane Handbook for Systematic Reviews of Interventions
    10. Higgins, 2019, Cochrane Handbook for Systematic Reviews of Interventions, 10.1002/9781119536604 · DOI · Paper page
    11. Sterne, 2019, Cochrane Handbook for Systematic Reviews of Interventions
    12. McKenzie, 2019, Cochrane Handbook for Systematic Reviews of Interventions

    Cited by

    Sorted by citations

    Authors
    Cumpston, M. S., McKenzie, J. E., Welch, V. A., & Brennan, S. E.
    Affiliations
    • University of Newcastle Australia (AU)
    • Monash University (AU)
    • University of Ottawa (CA)
    Corresponding author
    Cumpston, Miranda S
    Venue
    Journal of Public Health
    Published
    2022-03-28
    Volume
    44
    Issue
    4
    Pages
    e588-e592
    ISSN
    • 0943-1853 (ISSN-L)
    • 1741-3842
    • 1741-3850
    OpenAlex
    W4213435918
    Cited by
    464
    References
    24
    Citations by year
    2026: 114 · 2025: 133 · 2024: 147 · 2023: 54 · 2022: 15 · 2013: 1
    FWCI
    28.58
    Type
    journal article
    Language
    en
    Open access
    Locations
    • Journal of Public Health (publishedVersion, cc-by-nc)
    • PubMed Central (publishedVersion, cc-by-nc)
    • PubMed (publishedVersion)
    Funders
    • Australian National Health and Medical Research Council
    • Career Development Fellowship (1143429)
    Topics
    • Social Sciences › Decision Sciences › Statistics, Probability and Uncertainty › Meta-analysis and systematic reviews
    • Health Sciences › Medicine › Public Health, Environmental and Occupational Health › Clinical practice guidelines implementation
    • Social Sciences › Sociology and Political Science › Delphi Technique in Research
    Keywords
    systematic reviews, public health interventions, research question formulation, equity, intervention complexity, risk of bias assessment, methodological recommendations, evidence synthesis
    MeSH terms
    Systematic Reviews as Topic, Humans, Public Health, Public Health Practice, Bias

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