Item	Low risk	High risk	Unclear risk
Was the intervention independent of other changes?	Compelling arguments that the intervention occurred independently of other changes over time and the outcome was not influenced by other confounding variables/historic events during study period. If events/variables identified, note what they are	The intervention was not independent of other changes in time	Insufficient information to permit judgement of low or high risk
Was the shape of the intervention effect prespecified?	Point of analysis is the point of intervention OR a rational explanation for the shape of intervention effect was given by the author(s). Where appropriate, this should include an explanation if the point of analysis is NOT the point of intervention	It is clear that the shape of the intervention was not prespecified	Insufficient information to permit judgement of low or high risk
Was the intervention unlikely to affect data collection?	The intervention itself was unlikely to affect data collection (e.g. sources and methods of data collection were the same before and after the intervention)	The intervention itself was likely to affect data collection (e.g. any change in source or method of data collection reported)	Insufficient information to permit judgement of low or high risk
Was knowledge of the allocated interventions adequately prevented during the study?	The authors state explicitly that the primary outcome variables were assessed blindly, or the outcomes are objective, e.g. length of hospital stay. Primary outcomes are those variables that correspond to the primary hypothesis or question as defined by the authors	If the outcomes were not assessed blindly	Insufficient information to permit judgement of low or high risk
Were incomplete outcome data adequately addressed? (If some primary outcomes were assessed blindly or affected by missing data and others were not, each primary outcome can be scored separately)	Missing outcome measures were unlikely to bias the results (e.g. the proportion of missing data was similar in the pre‐ and post‐intervention periods or the proportion of missing data was less than the effect size, i.e. unlikely to overturn the study result)	Missing outcome data were likely to bias the results. Do not assume 100% follow up unless stated explicitly)	Insufficient information to permit judgement of low or high risk
Was the study free from selective outcome reporting?	There is no evidence that outcomes were selectively reported (e.g. all relevant outcomes in the methods section are reported in the results section)	If some important outcomes are subsequently omitted from the results	Insufficient information to permit judgement of low or high risk
Was the study free from other risks of bias?	There is no evidence of other risks of bias, e.g. should consider if seasonality is an issue (i.e. if January to June comprises the pre‐intervention period and July to December the post, could the 'seasons' have caused a spurious effect)	There is evidence that other risks of bias exist, such as seasonality	Insufficient information to permit judgement of low or high risk