Statistical methods for dealing with publication bias in meta-analysis.

Publication bias is an inevitable problem in the systematic review and meta-analysis. It is also one of the main threats to the validity of meta-analysis. Although several statistical methods have been developed to detect and adjust for the publication bias since the beginning of 1980s, some of them are not well known and are not being used properly in both the statistical and clinical literature. In this paper, we provided a critical and extensive discussion on the methods for dealing with publication bias, including statistical principles, implementation, and software, as well as the advantages and limitations of these methods. We illustrated a practical application of these methods in a meta-analysis of continuous support for women during childbirth.