The winner's curse: why large effect sizes in discovery trials always get smaller and often disappear completely.

The article discusses the phenomenon known as the "winner's curse" in medical research, where large effect sizes observed in small discovery trials often shrink or disappear in subsequent larger trials. The author explains that this effect is a consequence of null hypothesis significance testing and the need for larger trials to cross the significance threshold. The article also highlights the issue of publication bias, where trials reporting significant results are more likely to be published, leading to a skewed representation of the evidence. The author provides recommendations for interpreting effect sizes in small trials and emphasizes the importance of conducting larger trials to obtain more accurate estimates of treatment effects. [Extracted from the article]