PLACE:  319 Snedecor

SPEAKER:
Richard Tweedie
Division of Biostatistics, University of Minnesota

TITLE:
A Non-parametric “Trim and Fill” Method of Accounting for Publication Bias in Meta Analysis

ABSTRACT:
Meta-analysis collects and synthesizes results from individual studies to
estimate an overall effect size.  If published studies are chosen, say through
a literature review, an inherent selection bias may arise, since for example,
studies may tend to be published more readily if they are statistically
significant, or deemed to be more ‘interesting’ in terms of the impact of their
outcomes.

We develop a simple rank-based data augmentation technique, formalizing the use
of funnel plots, to estimate and adjust for the numbers and outcomes of missing
studies.  Several non-parametric estimators are proposed for the number of
missing studies, and their properties are developed analytically and through
simulations.  We apply the method to simulated and epidemiological data sets,
and show it is both effective and consistent with other criteria in the
literature.
 

COFFEE: 3:45 p.m., 104 Snedecor