Cochrane Bias Methods Group (BMG)

The Bias Methods Group (BMG) is one of 18 Cochrane Methods Groups world-wide comprised of individuals with an interest and expertise in the science of systematic reviews. This BMG strives to raise awareness of different sources of bias in research studies, which may affect the credibility of systematic reviews that include them, Examples of such biases include bias due to missing data, bias in measurement of outcomes, and bias due to selective reporting of results.


Activities of BMG members include:

  • Contributing to bias-relevant chapters of the Cochrane Handbook for Systematic Reviews of Interventions;
  • Development of tools to assess risk of bias, including the revised tool to assess risk of bias in randomized trials (RoB 2), and the Risk of Bias In Non-randomized Studies - of Interventions tool (ROBINS-I);
  • Undertaking empirical research to examine whether, and in which circumstances, various sources of bias may have a substantial impact on systematic reviews;
  • Undertaking methodological research on how to identify and address potential study biases in systematic reviews and meta-analyses;
  • Helping to complete and co-ordinate Cochrane Methodology Reviews pertinents to the Group's remit;
  • Providing advice to Cochrane entities on how to assess risk of bias; and
  • Offering training to both Cochrane and non-Cochrane systematic reviewers via formal and informal opportunities.


BMG is administered by Centre for Evidence-Based Medicine Odense (CEBMO) at Odense University Hospital (OUH) and University of Southern Denmark (SDU) and based in Odense, Denmark. 

BMG would like to thank Odense University Hospital  for their financial support.