Center For Mind, Brain, And Culture

In psychology (e.g., Schooler, 2011) and other fields (e.g., Jennions & Møller, 2001), there are reported cases of effect sizes declining over time. Later studies of a given phenomenon report smaller effect sizes than earlier studies. This decline suggests a publication bias toward large effects and regression to the mean. In the current study, we examine whether evidence exists for such a decline effect. In Study 1, we analyzed 3,488 effect sizes across 70 meta-analytic tables, which were drawn from 33 Psychological Bulletin articles (1980–2010). A multilevel analysis revealed no evidence of a linear or quadratic decline effect over time (indexed by publication year). In Studies 2 and 3, we examined 50 meta-analyses each from social psychology and clinical psychology. In both studies, the modal meta-analysis showed no correlation between effect size and publication year. The decline effect in psychology appears to be less prevalent than earlier anecdotal reports suggest. For replications, this finding su