On the Poor Statistical Properties of theP-Curve Meta-Analytic Procedure
Richard D. Morey, Clintin P. Davis-Stober
Journal of the American Statistical Association · 2026 · Volume 121 · Issue 553
DOI: 10.1080/01621459.2025.2544397
Abstract
The P -curve is a widely used suite of meta-analytic tests advertised for detecting problems in sets of studies. They are based on nonparametric combinations of p values (e.g., Marden) across significant ( p < .05) studies and are variously claimed to detect “evidential value”, “lack of evidential value”, and “left skew” in p values. We show that these tests do not have the properties ascribed to them. Moreover, they fail basic desiderata for tests, including admissibility and monotonicity. In light of these serious problems, we recommend against the use of the P -curve tests. Supplementary materials for this article are available online, including a standardized description of the materials available for reproducing the work.
Keywords
Admissibility, Inference, Meta-analysis
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