Background: Few validated checklist tools are available to assess the risk of bias (RoB) of non-randomized studies (NRS), although systematic reviews including NRS have increased in number, for many reasons.
Objectives: The aims of the study are to develop and validate a new RoB tool for NRS.
Methods: After deciding principles and reviewing relevant tools, we developed the Risk of Bias Assessment tool for Non-randomized Studies (RoBANS) tool. Subsequent testing involved the assessment of inter-rater agreement between reviewers, time to apply the RoBANS tool, degree of correlation for overall risk compared with overall quality scores, user-convenience, and content validity.
Conclusions: RoBANS is a valid tool designed to assess the RoB of NRS. Since RoBANS is harmonized with the Cochrane’s RoB tool and GRADE (Grading of Recommendations Assessment, Development and Evaluation), and can be incorporated into RevMan and GRADEpro, it appears to be useful to people undertaking systematic reviews.