Small study effects and reporting biases
In some meta-analyses, we find that small studies have systematically different effects to the large studies. This can have many causes, but one is the possibility of reporting bias - that is, we might be missing small studies with negative effects because they are unpublished or less accessible than larger studies.
Approved by the Cochrane Methods Board on 5 October 2011.
Compiled by Miranda Cumpston, based on materials by Jonathan Sterne, Matthias Egger, Julian Higgins, David Moher, Nancy Santesso, Holger Schünemann, the Cochrane Bias Methods Group, the Australasian Cochrane Centre and the Cochrane Applicability and Recommendations Methods Group.