Publication Bias in Meta-Analysis: Its Meaning and Analysis
AUTHOR : 황성동
INFORMATION : page. 1~19 / 2016 Vol.23 No.1
ABSTRACT
As a new mode of research synthesis, meta-analysis has recently drawn much attention from researchers,
having proved to produce less biased results than the traditional research synthesis method. However,
scholars may be suspicious about the results of meta-analysis due to publication bias as it occurs when
published studies represent a biased selection of the evidence. This study was designed to discuss the
meaning of publication bias and conduct publication bias analysis using an example data set so as to
provide researchers with a guideline for performing valid meta-analysis. The process of publication bias
analysis begins with a careful examination of the effect sizes of individual studies and continues with
testing funnel plot asymmetry. With both a graphical test and a statistical one, potential publication bias
could not be ruled out. To deal with this bias, adjustments were made using the trim-and-fill method
followed by the Copas selection model, and the original result was found to be valid and statistically
robust even with the small bias detected. In the academic circle of meta-analysis, publication bias analysis
is specified as one of the required items in some guidelines of reporting and evaluating the results of
meta-analysis. Therefore, it is highly recommended to conduct publication bias analysis for the validity of
meta-analysis as well as the integrity of individual meta-analytic studies.