Extending the risk of bias tool to allow for assessment of non-randomised studies, cluster-randomised trials and cross-over trials: a Cochrane methods innovation fund project

Sterne J1, Higgins J2, Reeves B1, Savovic J1, Turner L3, Members and leads of eight other working groups T4
1University of Bristol, United Kingdom, 2Methods Executive, United Kingdom, 3Ottawa Hospital Research Institute, Canada, 4Bias Methods and Non-randomised Studies Methods Group


To introduce a proposed extension to the Cochrane risk of bias tool allowing risk of bias assessment of non-randomised studies, cluster-randomised trials and cross-over trials, and to solicit feedback and identify potential areas for improvement which should be addressed.


The Collaboration needs a tool to assess the potential risk of bias in non-randomised studies. The Cochrane Methods Innovation Fund has commissioned a project, led by the Bias Methods Group and the Non-Randomised Studies Methods Group to extend the existing Risk of Bias tool to address non-randomised studies, as well as to address variations on randomised trial designs not well covered by the existing tool (specifically cluster-randomised trials and cross-over trials). Working groups have been focusing on different aspects of bias or study design, and a provisional tool has emerged. This discussion workshop will introduce the project, present the current version of the extended tool and provide an opportunity for discussion of potential concerns or questions. The objective of the workshop is to highlight areas for development which have not already been addressed and which should be considered prior to the tool being disseminated collaboration wide. Considerations for discussion will include scientific issues, feasibility issues, roll-out and training opportunities.