Does Scientific Productivity Increase the Publication of Positive Results?

Abstract

The overrepresentation of positive results in psychology is often attributed in part to publication bias. However, the impact of research group output on the prevalence of positive results has not yet been investigated. The present study examines whether German clinical psychology research groups with high versus low publication outputs differ in the prevalence of positive outcomes in their publications. Scientific productivity was defined as the ratio of quantitative-empirical publications to the number of academic staff per chair. We analyzed publications authored by clinical psychology researchers at German universities from 2013 to 2022, sourced from PubMed and OpenAlex. After excluding meta-analyses, reviews, and non-empirical studies, 2,280 empirical studies from 99 research groups were identified. We then randomly sampled and coded 300 papers, evenly split between the highest and lowest output quartiles, and examined the first hypothesis. There was no statistically significant difference between the highest and the lowest output quartiles, with both reporting approximately 90% positive results. Higher group paper counts were not associated with more positive results. Exploratory abstract-level analyses showed no significant differences in positive result rates between all four output quartiles. Our results suggest a general excess of positive results in clinical psychology. Contrary to our hypothesis, German clinical psychology research groups with high and low publication outputs do not differ in the prevalence of positive outcomes in their publications.