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Table 3 Risk of bias assessment of study by Salmon et al. [18]a

From: A systematic review of hospital accreditation: the challenges of measuring complex intervention effects

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
  1. aThe risk of bias assessment as described in the Cochrane Handbook for randomized controlled trails [20]
  2. Risk of bias assessment of the included primary study by Salmon el at [18]
  3. SOURCE: Higgins J, Green S. Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 [updated March 2011]. The Cochrane Collaboration, 2011