Article type
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Abstract
Background: Overviews of reviews (overviews) compile data from multiple systematic reviews (SRs) to provide a single synthesis of relevant evidence for healthcare decision-making. Despite their increasing popularity, there is limited methodological guidance available for researchers wishing to conduct overviews.
Objectives: To identify and collate all published and unpublished documents containing methodological guidance for conducting overviews. Our aims were to: provide a map of existing guidance documents; identify similarities, differences, and gaps in guidance; and identify common challenges involved in conducting overviews.
Methods: We conducted a comprehensive search that involved reference tracking, database searches, handsearching websites and conference proceedings, and contacting overview producers. Guidance statements across included documents were analyzed by stage of the overview process using a qualitative meta-summary approach.
Results: We identified 52 guidance documents produced by 19 author groups between 2004-2015; 69% were produced by authors affiliated with Cochrane, and 71% were unpublished documents not accessible through traditional database searching. Adequate guidance was available for: deciding whether to conduct an overview, specifying the scope, and searching for and including SRs. Limited or conflicting guidance was available for: quality assessment of SRs, collecting and analyzing data, and grading quality of evidence. Major challenges identified were deciding whether and how to include multiple SRs examining the same intervention for the same disorder, and dealing with data that are missing, inadequately reported, or reported differently across SRs.
Conclusions: This is the first systematic and comprehensive compilation of methodological guidance for conducting overviews. Results of this project will facilitate the production of future overviews and can help authors address key challenges they are likely to encounter. Results have been used to update the guidance contained within the Cochrane Handbook's chapter on overviews, and can be used to set priorities for future methods research.
Objectives: To identify and collate all published and unpublished documents containing methodological guidance for conducting overviews. Our aims were to: provide a map of existing guidance documents; identify similarities, differences, and gaps in guidance; and identify common challenges involved in conducting overviews.
Methods: We conducted a comprehensive search that involved reference tracking, database searches, handsearching websites and conference proceedings, and contacting overview producers. Guidance statements across included documents were analyzed by stage of the overview process using a qualitative meta-summary approach.
Results: We identified 52 guidance documents produced by 19 author groups between 2004-2015; 69% were produced by authors affiliated with Cochrane, and 71% were unpublished documents not accessible through traditional database searching. Adequate guidance was available for: deciding whether to conduct an overview, specifying the scope, and searching for and including SRs. Limited or conflicting guidance was available for: quality assessment of SRs, collecting and analyzing data, and grading quality of evidence. Major challenges identified were deciding whether and how to include multiple SRs examining the same intervention for the same disorder, and dealing with data that are missing, inadequately reported, or reported differently across SRs.
Conclusions: This is the first systematic and comprehensive compilation of methodological guidance for conducting overviews. Results of this project will facilitate the production of future overviews and can help authors address key challenges they are likely to encounter. Results have been used to update the guidance contained within the Cochrane Handbook's chapter on overviews, and can be used to set priorities for future methods research.