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Table 6 Methods and approaches for addressing common scenarios unique to overviews

From: Toward a comprehensive evidence map of overview of systematic review methods: paper 2—risk of bias assessment; synthesis, presentation and summary of the findings; and assessment of the certainty of the evidence

  Scenario for which authors need to plan Methods/approaches proposed in the literaturea
Assessment of RoB in SRs and primary studies (Table 3) Synthesis, presentation and summary of the findings (Table 4) Assessment of certainty of the evidence (Table 5)
1 Reviews include overlapping information and data (e.g. arising from inclusion of the same primary studies) 2.1.1 1.1.2, 5.0 1.1.1–1.1.5
2 Reviews report discrepant information and data 2.1.1, 2.1.2, 2.1.3 2.2.1, 2.2.5 1.1.1–1.1.5
3 Data are missing or reviews report varying information (e.g. information on risk of bias is missing or varies across primary studies because reviews use different tools) 2.1.1, 2.1.3 1.2.9, 2.2.1, 2.2.5 1.1.1–1.1.5
4 Reviews provide incomplete coverage of the overview question (e.g. missing comparisons, populations)   2.2.1, 2.2.4 1.1.1, 1.1.2, 1.1.5
5 Reviews are not up-to-date   2.2.2 1.1.1, 1.1.2
6 Review methods raise concerns about bias or quality 2.1.1, 2.1.2, 2.2.3 2.2.3, 2.2.5, 4.0 1.1.1–1.1.5
7 Reviews report discordant results and conclusions   2.2.7, 6.0 1.1.1–1.1.5
  1. aThe methods/approaches could be used in combination and at several steps in the conduct of an overview. When one approach is taken, then another approach may not apply