Review authors’ judgements involve answering a specific question for each entry. In all cases, an answer ‘Yes’ indicates a low risk of bias, and an answer ‘No’ indicates high risk of bias.
provides criteria for making judgements about risk of bias from each of the six domains in the tool. If insufficient detail is reported of what happened in the study, the judgement will usually be ‘Unclear’ risk of bias. An ‘Unclear’ judgement should also be made if what happened in the study is known, but the risk of bias is unknown; or if an entry is not relevant to the study at hand (particularly for assessing blinding and incomplete outcome data, when the outcome being assessed by the entry has not been measured in the study).