On the correlation between effect size and sample size: A reply

Abstract

In a comment on our paper, Bradley and Brand (2013) argue that effect sizes are exaggerated owing to low power and publication bias. They propose to correct these exaggerations by application of a specific formula leading to a better estimate of the “true” effect size. In a simulation we test the effect of this formula and find this “corrective” approach unsatisfactory. We agree with Bradley and Brand on the points that effect sizes are important in primary and secondary research, and that exaggerated effect sizes are a serious problem in research. However, we disagree on the appropriate reaction: A diagnostic approach may be more appropriate than a corrective approach.