Critical appraisal of studies assessed within a systematic review is primarily determined by an assessment of the risk of bias of each study. Within RevMan, the ‘Characteristics of included studies' table has five entries for each study: Methods, Participants, Interventions, Outcomes, and Notes. Up to three further columns may be specified for items not covered by these categories, for example, to provide information on length of follow-up or funding source.
The ‘Risk of bias' table is an extension of the 'Characteristics of included studies' table and shows the items for assessment: Sequence generation, Allocation sequence concealment, Blinding, Incomplete outcome data, Selective outcome reporting, and Other bias. For each item, the review authors must judge the item to be at low risk of bias, high risk of bias, or unclear. Support for the judgement that has been made about each study must be stated within the table.
For more information, please see the Cochrane Handbook (www.cochrane-handbook.org). The 'Risk of bias' tables are discussed in Chapter 8, and guidance on 'Characteristics of included' studies tables is provided in Chapter 11 (Section 11.2).