Insights & Perspectives
Optimizing α for better statistical decisions: A case study involving the pace-of-life syndrome hypothesis
Optimal α levels set to minimize Type I and II errors frequently result in different conclusions from those using α = 0.05
Article first published online: 19 OCT 2012
Copyright © 2012 WILEY Periodicals, Inc.
Volume 34, Issue 12, pages 1045–1049, December 2012
How to Cite
Mudge, J. F., Penny, F. M. and Houlahan, J. E. (2012), Optimizing α for better statistical decisions: A case study involving the pace-of-life syndrome hypothesis. Bioessays, 34: 1045–1049. doi: 10.1002/bies.201200120
- Issue published online: 14 NOV 2012
- Article first published online: 19 OCT 2012
- effect size;
- hypothesis testing;
- optimal α;
- statistical power
Setting optimal significance levels that minimize Type I and Type II errors allows for more transparent and well-considered statistical decision making compared to the traditional α = 0.05 significance level. We use the optimal α approach to re-assess conclusions reached by three recently published tests of the pace-of-life syndrome hypothesis, which attempts to unify occurrences of different physiological, behavioral, and life history characteristics under one theory, over different scales of biological organization. While some of the conclusions reached using optimal α were consistent to those previously reported using the traditional α = 0.05 threshold, opposing conclusions were also frequently reached. The optimal α approach reduced probabilities of Type I and Type II errors, and ensured statistical significance was associated with biological relevance. Biologists should seriously consider their choice of α when conducting null hypothesis significance tests, as there are serious disadvantages with consistent reliance on the traditional but arbitrary α = 0.05 significance level.