Cochrane Interactive Learning

Module 5: Introduction to risk of bias

About this module

Part of the Cochrane Interactive Learning course on Conducting an Intervention Review, this module explains what bias is, and why and how to assess risk of bias. In this module you will learn about the difference between study quality and risk of bias, and how to assess the range of sources of bias in randomized trials.

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Duration 90-120 minutes

What you can expect to learn (learning outcomes)

This module will teach you to:

  • Assess the risk of bias arising from the randomization process in the included studies
  • Assess the risk of bias due to deviations from the intended interventions in the included studies
  • Assess the risk of bias due to missing outcome data in the included studies
  • Assess the risk of bias in measurement of the outcome in the included studies
  • Assess the risk of bias due to selective reporting
  • Reach a judgement on the overall 'risk of bias' in the included studies
  • Identify ways of incorporating ‘Risk of bias’ assessment into the analysis

Authors, contributors, and how to cite this module

Module 5 has been written and compiled by:

Matthew J. Page, School of Social and Community Medicine, University of Bristol, UK, and School of Public Health & Preventive Medicine, Monash University, Australia.

Julian Higgins, School of Social and Community Medicine, University of Bristol, UK.

Dario Sambunjak, Miranda Cumpston and Chris Watts, Cochrane Central Executive Team.

A full list of acknowledgements, including our expert advisors from across Cochrane, is available at the end of each module page. 

This module should be cited as: Page MJ, Higgins J, Sambunjak D, Cumpston M, Watts C. Module 5: Introduction to study quality and risk of bias. In: Cochrane Interactive Learning: Conducting an intervention review. Cochrane, 2017. Available from https://training.cochrane.org/interactivelearning/module-5-introduction-study-quality-and-risk-bias.

Update and feedback

The module was last updated on September 2022.

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