Assessing risk of bias in included studies


A Cochrane systematic review is only as good as its included studies. Biases can lead to systematic errors or deviations from the true effect of an intervention in the results of a review, and it is important to carefully assess the possible risk of bias in all included studies. The slidecast presentation explains the concept of risk of bias and presents the Cochrane Risk of Bias tool. It also describes different types of biases and possible ways of identifying and avoiding them.

The presentation has been translated into several languages other than English. Select an available language from the list at the top right of this page.

After using this resource, you should be able to...
  • Describe what is risk of bias in included studies and why it is important to assess it
  • Recognize different sources of bias in included studies
  • Identify possible ways of avoiding risk of bias
  • Plan the risk of bias assessment in your systematic review
  • Identify the elements of the 'Risk of bias' tables in RevMan
  • Incorporate and summarize findings of the risk of bias assessment in your review

Assessing risk of bias - slidecast

Author information: 
Cumpston, Miranda

Approved by the Cochrane Methods Board on 5 October 2011.

Compiled by Miranda Cumpston, based on materials by the Cochrane Bias Methods Group and the Australasian Cochrane Centre.