Domain	Review authors’ judgement	Support for judgement
Selection bias	Random sequence generation*	High, Unclear, or Low risk?	Describe the method used to generate the allocation sequence in sufficient detail to allow an assessment of whether it should produce comparable groups. (Adequate: random number table, computer generated. Inadequate: alternation, DOB, date of admission, hospital number) If you are including only RCTs in your review, papers marked ‘high risk’ should be excluded as they are not truly randomised.
	Allocation concealment	High, Unclear, or Low risk?	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. (Decision to accept or reject a participant must be made without knowledge of the treatment assigned) (Adequate: centralised randomisation or sequentially numbered opaque envelopes Inadequate: open list of random numbers, coin toss, alternation Unclear: just stating that a table, list or sealed envelopes were used)
Performance bias	Blinding of participants and personnel Assessments should be made for each main outcome (or class of outcomes)	High, Unclear, or Low risk?	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.
Detection bias	Blinding of outcome assessment Assessments should be made for each main outcome (or class of outcomes).	High, Unclear, or Low risk?	Describe all measures used, if any, to blind outcome assessors from knowledge of which intervention a participant received. Provide any information relating to whether the intended blinding was effective. If the outcome is objective (eg. length of hospital stay) the rating should be ‘Low risk'
Attrition bias	Incomplete outcome data Assessments should be made for each main outcome (or class of outcomes).	High, Unclear, or Low risk?	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 randomised participants), reasons for attrition/exclusions where reported, and any re‐inclusions in analyses performed by the review authors (ITT)
Reporting bias	Selective reporting	High, Unclear, or Low risk?	State how the possibility of selective outcome reporting was examined by the review authors, and what was found.
Other bias	Other sources of bias See the Cochrane Handbook 8.15.1 for further examples of potential threats to validity.	High, Unclear, or Low risk?	State any important concerns about bias not addressed in the other domains in the tool. If particular questions/entries were pre‐specified in the review’s protocol, responses should be provided for each question/entry (early stopping, baseline imbalances, choice of design, funding source)