title: A peculiar prevalence of p values just below .05.
abstract: In null hypothesis significance testing (NHST), p values are judged relative to an arbitrary threshold for significance (.05). The present work examined whether that standard influences the distribution of p values reported in the psychology literature. We examined a large subset of papers from three highly regarded journals. Distributions of p were found to be similar across the different journals. Moreover, p values were much more common immediately below .05 than would be expected based on the number of p values occurring in other ranges. This prevalence of p values just below the arbitrary criterion for significance was observed in all three journals. We discuss potential sources of this pattern, including publication bias and researcher degrees of freedom.
authors.affiliation: Department of Psychology, Wake Forest University, Winston-Salem, NC 27109, USA. masicaej@wfu.edu
authors.forename: E J
authors.initials: EJ
authors.lastname: Masicampo
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Lalande
mesh_terms: D016206:Databases, Bibliographic / Q000706:statistics & numerical data; D006801:Humans; D015995:Prevalence; D011336:Probability; D011584:Psychology; D017594:Publication Bias; D013223:Statistics as Topic