THE FILE-DRAWER PROBLEM REVISITED: A GENERAL WEIGHTED METHOD FOR CALCULATING FAIL-SAFE NUMBERS IN META-ANALYSIS

A general, weighted fail‐safe calculation, grounded in the meta‐analysis framework, applicable to both fixed‐ and random‐effects models, is proposed.

Abstract

Quantitative literature reviews such as meta-analysis are becoming common in evolutionary biology but may be strongly affected by publication biases. Using fail-safe numbers is a quick way to estimate whether publication bias is likely to be a problem for a specific study. However, previously suggested fail-safe calculations are unweighted and are not based on the framework in which most meta-analyses are performed. A general, weighted fail-safe calculation, grounded in the meta-analysis framework, applicable to both fixed- and random-effects models, is proposed. Recent meta-analyses published in Evolution are used for illustration.