A Methodological Metamorphosis: The Rapid Rise of Bayesian Inference and Open Science Practices in Psychology

The field of psychology is in the midst of a methodological revolution. To quantify the changes, we tracked the adoption of Bayesian inference and open science practices across 15,634 empirical articles from six leading psychology journals over a twenty-year period (2004–2024). Human (50%) and LLM-assisted (50%) full-text coding revealed that in 2024, about 1 in every 4 articles (26%) reported a Bayesian analysis, about 2 in every 5 articles (40%) included a preregistration, and about 3 in every 4 articles (73%) provided open data. From 2004 to 2012, these practices were virtually nonexistent. Application of a Bayesian logistic growth model suggests these practices will continue to rise in the future, although the extent of their growth remains uncertain. In addition, our review revealed that mixed-effects models have become more prevalent; software reporting has improved, with growing use of R alongside a relative decline of SPSS; and that estimation-focused reporting showed only modest gains. Despite considerable heterogeneity between journals, our results present a detailed account of the ways in which articles from 2024 differ methodologically from those that were published only a decade before.