Evidence-appraisal glossary
RoB 2
Cochrane's structured tool for judging risk of bias in randomized trials. It walks a reviewer through set questions across several domains and yields a rating of low risk, some concerns, or high risk of bias.
Also called: revised Cochrane risk-of-bias tool.
RoB 2 organizes bias into domains such as the randomization process, deviations from intended interventions, missing outcome data, measurement of the outcome, and selection of the reported result. Each domain is answered with signaling questions, and those answers drive an overall judgment for one specific result rather than the whole trial. Because the same trial can look different depending on which effect is being estimated, RoB 2 asks the reviewer to name the estimand first.
This is a plain-language methodology definition for reading research. It is general education, not medical advice.