Lifeng Lin ColloquiumThursday, October 26, 2017 - 2:45pm
Statistics Department Colloquium
Where: LeConte College, Room 210
Speaker: Lifeng Lin
Affiliation: Florida State University
Assessing Publication Bias in Meta-Analysis
Abstract: Publication bias is a serious problem in systematic reviews and meta-analyses, which can jeopardize the validity and generalization of conclusions. Current approaches to dealing with publication bias can be distinguished into two classes: selection models and funnel-plot-based methods. Although various statistical methods are available to assess publication bias, their performance has not been systematically evaluated by comprehensive real applications. We compare several commonly-used publication bias tests and evaluate their agreements based on a large collection of meta-analyses from the Cochrane Library. The agreements among most tests are found to be low or moderate. In addition, so far it is popular to test for publication bias, while measures for quantifying publication bias are seldom studied in the literature. Such measures can be used as a characteristic of a meta-analysis, and they permit comparisons of publication biases between different meta-analyses. Egger’s regression intercept is a candidate measure, but it lacks an intuitive interpretation. We introduce a new measure, the skewness of the standardized deviates, to quantify publication bias. This measure describes the asymmetry of the collected studies’ distribution. Also, a new test for publication bias is derived based on the skewness. Large sample properties of the new measure are studied, and its performance is illustrated using simulations and case studies.