Publication Bias 15

Learning objectives

• Understand what publication bias is and describe how it could arise
• Be familiar with the design and interpretation of funnel plots
• Be aware of other relationships which can cause funnel plot asymmetry
• Be aware of other forms of bias in the reporting of studies, especially duplicate publication, selective reporting of outcomes and subscales, and subgroups of data.
• Consider methods of reducing the potential impact of publication bias on the results of a systematic review
• Be aware of ongoing research in this field

Other relevant material

• Power Point presentation on reading a funnel plot

Relevant sections of the Reviewers’ Handbook

• Section 8.11

Where does this go in a Cochrane review?

• Ensure your search strategy is as sensitive as it can be to reduce the chances of missing negative studies, possibly attempt to measure publication bias as part of the analysis of your review in RevMan and consider the likelihood of publication bias in your review’s Discussion.