Objective: Publication bias threatens the validity of published research, although this topic has received little attention in psychiatry. The purpose of this article is to produce a systematic overview of the causes and consequences of publication bias and to summarize the available methods with which it is detected and corrected.
Method: Empirical evidence for the existence of publication bias is reviewed and the following methods are applied to an illustrative case example from psychiatry: funnel plot analysis; the ‘file drawer method’; linear regression techniques; rank correlation; ‘trim and fill’.
Results: Small studies are particularly susceptible to publication and related bias. All methods to detect publication bias depend upon the availability of a number of individual studies with a range of sample sizes. Unfortunately, large numbers of studies of varying sample size are not always available in many areas of psychiatric research.
Conclusion: Where possible researchers should always test for the presence of publication bias. The problem of publication bias will not be solved by anything other than a prospective trials register.