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Table 1 The original risk of bias tool

From: Evaluation of the Cochrane Collaboration’s tool for assessing the risk of bias in randomized trials: focus groups, online survey, proposed recommendations and their implementation

Domain Description Review authors’ judgement
Sequence generation Describe the method used to generate the allocation sequence in sufficient detail to allow an assessment of whether it should produce comparable groups Was the allocation sequence adequately generated?
Allocation concealment Describe the method used to conceal the allocation sequence in sufficient detail to determine whether intervention allocations could have been foreseen in advance of, or during, enrolment Was allocation adequately concealed?
Blinding of participants, personnel and outcome assessors. Assessments should be made for each main outcome (or class of outcomes) Describe all measures used, if any, to blind study participants and personnel from knowledge of which intervention a participant received. Provide any information relating to whether the intended blinding was effective Was knowledge of the allocated intervention adequately prevented during the study?
Incomplete outcome data. Assessments should be made for each main outcome (or class of outcomes) Describe the completeness of outcome data for each main outcome, including attrition and exclusions from the analysis. State whether attrition and exclusions were reported, the numbers in each intervention group (compared with total randomized participants), reasons for attrition/exclusions where reported, and any re-inclusions in analyses performed by the review authors Were incomplete outcome data adequately addressed?
Selective outcome reporting State how the possibility of selective outcome reporting was examined by the review authors, and what was found Are reports of the study free of suggestion of selective outcome reporting?
Other sources of bias State any important concerns about bias not addressed in the other domains in the tool Was the study apparently free of other problems that could put it at a high risk of bias?
  If particular questions/entries were pre-specified in the review’s protocol, responses should be provided for each question/entry  
  1. Based on Higgins and Altman[6]. The original tool was in use at the time focus groups and survey were administered (September 2009 to February 2010).