[Skip to Content]
Access to paid content on this site is currently suspended due to excessive activity being detected from your IP address Please contact the publisher to request reinstatement.
[Skip to Content Landing]
Comment & Response
September 4, 2018

Lowering the P Value Threshold

Author Affiliations
  • 1Department of Pharmacy and Therapeutics, University of Pittsburgh School of Pharmacy, Pittsburgh, Pennsylvania
  • 2Division of General Internal Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
  • 3Insurance Services Division, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
JAMA. 2018;320(9):935. doi:10.1001/jama.2018.8733

To the Editor The Viewpoint by Dr Ioannidis discussed the recent proposal by a coalition of 72 methodologists to lower the statistical significance threshold to .005.1,2 Ioannidis acknowledged limitations of this proposal; however, his Viewpoint did not discuss any financial implications of this change.1 Powering randomized clinical trials (RCTs) and prospective observational studies at an α level of .005 would translate into considerably higher costs associated with larger sample sizes.