Table 1 Characteristics of methods studies on overlapping primary study data across reviews
Author Year | Title | Type of study | Method | Objective |
|---|---|---|---|---|
Descriptive studies | ||||
    Ballard 2017 [29] | Risk of bias in overviews of reviews: a scoping review of methodological guidance and four-item checklist | Article describing methods for overviews of systematic reviews of interventions | Scoping review of guidance and methods | Synthesise guidance on overview practice |
    Bougioukas 2020 [33] | Methods for depicting overlap in overviews of systematic reviews: An introduction to static tabular and graphical displays | Article describing methods for overviews of systematic reviews of interventions | Selective review of papers presenting graphs | Present graphs for visually presenting overlap |
    Hennessy 2019 [30] | Best practice guidelines and essential methodological steps to conduct rigorous and systematic meta-reviews | Article describing methods for overviews of systematic reviews of interventions | Literature review of methods | Described six steps to address challenges in overviews |
    Hennessey 2020 [17] | Examining overlap of included studies in meta-reviews: guidance for using the corrected covered area index | Article describing methods for overviews of systematic reviews of interventions | Elaboration of an established method | Described five steps when examining overlap, illustrated through an example |
    Pollock A. 2017 [18] | Selecting and implementing overview methods: implications from five exemplar overviews | Article examining methods used in a cross-section or cohort of overviews | Elaboration of an established method | Describes methodological challenges of five overviews |
    Pollock M. 2019 [28] | Chapter V: Overviews of reviews. In Cochrane Handbook for Systematic Reviews of Interventions v 6.0 | Guidance for undertaking overviews | Guidance document | Guidance on how and when to assess overlap across primary studies |
    Pollock M. 2019 [31] | A decision tool to help researchers make decisions about including systematic reviews in overviews of reviews of healthcare interventions | Guidance for undertaking overviews | Decision tool | Systematically conducted seven overviews five times each, making five different decisions about which systematic reviews to include |
    Pérez-Bracchiglione 2019 [32] | Graphical representation of overlap degree of primary studies in systematic reviews in overviews [abstract OS29.1] | Articles describing methods for overviews of systematic reviews of interventions | Elaboration of an established method | Outlines an overlap assessment tool based on the corrected covered area (CCA [13]) |
Empirical study | ||||
    Pollock M. 2019 [19] | The impact of different inclusion decisions on the comprehensiveness and complexity of overviews of reviews of healthcare interventions | Empirical study | Empirical study of an established method | Assessed the impact of five inclusion decisions on the outcome data lost and changed |