• English
  • Español

Investigating and dealing with bias in systematic reviews

Topic category Investigating bias
Date and Location
Thursday 20 October 2011 - 14:00 - 15:30
Methods Group
Methods Group: 
Bias Methods Group
Contact person
Contact person: 
Lucy-Ann Turner (Contact this person)
First nameLast nameAffiliation and Country
First name: 
Last name: 
Affiliation and Country: 
Ottawa Hospital Research Institute
Other contributors
First nameLast nameAffiliation and Country
First name: 
Last name: 
Affiliation and Country: 
University of Bristol, UK
First name: 
Last name: 
Affiliation and Country: 
Université Paris 7 Denis Diderot, France
First name: 
Last name: 
Affiliation and Country: 
Ottawa Hospital Research Institute, Canada
Target audience
Target audience: 
Suitable for all
Is your workshop restricted to a specific audience or open to all Colloquium participants?: 
Level of knowledge required: 
Type of workshop
Type of workshop: 
Abstract text
To introduce the different forms of bias that can affect systematic review results, and the methods that can be used to detect and address these biases.

The results of a systematic review can be distorted if bias has been introduced into the review process at any stage. Investigation of the presence, degree, and nature of bias is recommended as a routine part of the systematic review process. The Cochrane Handbook for Systematic Reviews of Interventions contains chapters on “Addressing reporting biases” and “Assessing risk of bias in included studies”; the authors and workshop facilitators are the co-Convenors of the Bias Methods Group. We will discuss potential biases that might be introduced into reviews, with an emphasis on reporting biases and the effects of flaws in the methodology of component studies. Particular attention will be paid to publication bias, other reporting biases including outcome selection bias, and the empirical evidence on sources of bias in the results of randomised controlled trials. We will demonstrate and discuss graphical and statistical methods that can be used to examine bias, including funnel plots and meta-regression. We will discuss how review authors should incorporate Risk of Bias assessments in meta-analyses.