Post hoc power analysis: An idea whose time has passed?

Using a hypothetical scenario typifying the experience that authors have wh en submitting manuscripts that report results of negative clinical trials, the pitfalls of a post hoc analysis are illustrated. We used the same scena rio to explain how confidence intervals are used in interpreting results of clinical trials. We showed that confidence intervals better inform readers about the possibility of an inadequate sample size than do post hoc power calculations.