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Using Risk of Bias 2 to assess results from randomised controlled trials: guidance from Cochrane
Ella Flemyng1, Theresa Helen Moore2,3, Isabelle Boutron4,5
1Cochrane Evidence Production and Methods Directorate, Cochrane, London, UK.
BMJ Evidence-Based Medicine
|January 24, 2023
Summary
Systematic reviews assess study bias using explicit methods. This paper details learnings from implementing Risk of Bias 2 (RoB 2), an updated tool for assessing bias in randomized controlled trials.
Area of Science:
- Medical Research Methodology
- Evidence Synthesis
- Biostatistics
Background:
- Systematic reviews are crucial for synthesizing empirical evidence.
- Assessing risk of bias in studies enhances confidence in review conclusions.
- The Cochrane Collaboration has used a risk of bias tool for randomized controlled trials since 2008.
Approach:
- This paper discusses the implementation of Risk of Bias 2 (RoB 2), the updated version of the Cochrane risk of bias tool.
- The implementation involved a phased approach with user feedback guiding development.
- The paper highlights differences between the original tool and RoB 2.
Key Points:
- Risk of Bias 2 (RoB 2) was launched in 2019 to improve usability and reflect current understanding of bias.
- The phased implementation provided valuable learning experiences for systematic reviewers.
- Guidance development was informed by user input during the implementation process.
Conclusions:
- The paper shares insights and practical tips for systematic reviewers utilizing RoB 2.
- It emphasizes the importance of updated tools for accurate bias assessment in systematic reviews.
- Lessons learned from the RoB 2 implementation benefit both Cochrane and non-Cochrane systematic reviews.
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