Table 3.

Risk of bias assessment of study by Salmon et al. [18]^a

Domain	Support for judgement	Review author’s judgement
Selection bias
Random sequence generation	They state stratified randomisation, but give no information about the procedure	Unclear
Allocation concealment	Not mentioned	Unclear
Performance bias
Blinding of participants and personnel	Not mentioned and appears impossible/not possible to blind hospitals	Unclear
Detection bias
Blinding of outcome assessor	Not mentioned	Unclear
Attrition bias
Incomplete outcome date	The largest hospital did not complete the study. Follow- up time was shortened because controls wanted to receive the intervention	High risk
Reporting bias
Selective reporting	Outcome selection conducted by participants and accreditor. Many outcomes/ indicators were dropped from the follow- up measurement	High risk
Other bias
Other sources of bias	This was a cluster randomized trial, adjustment for clustering in analysis of results were not mentioned	Unclear

^aThe risk of bias assessment as described in the Cochrane Handbook for randomized controlled trails [20]

Risk of bias assessment of the included primary study by Salmon el at [18]

SOURCE: Higgins J, Green S. Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 [updated March 2011]. The Cochrane Collaboration, 2011