Volume 21, Issue 4 p. 405-409

Post Hoc Power Analysis: An Idea Whose Time Has Passed?

Marc Levine Ph.D.

Corresponding Author

Marc Levine Ph.D.

Faculty of Pharmaceutical Sciences, University of British Columbia, and the Department of Pharmacy, Children's and Women's Health Centre of British Columbia, Vancouver, British Columbia, Canada

Faculty of Pharmaceutical Sciences, University of British Columbia 2146 East Mall, Vancouver, British Columbia, Canada V6T 1Z3Search for more papers by this author
Mary H. H. Ensom Pharm.D., FASHP, FCCP

Mary H. H. Ensom Pharm.D., FASHP, FCCP

Faculty of Pharmaceutical Sciences, University of British Columbia, and the Department of Pharmacy, Children's and Women's Health Centre of British Columbia, Vancouver, British Columbia, Canada

Search for more papers by this author
First published: 17 January 2012
Citations: 321

Abstract

Using a hypothetical scenario typifying the experience that authors have when submitting manuscripts that report results of negative clinical trials, the pitfalls of a post hoc analysis are illustrated. We used the same scenario 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.