Files and links (2)
CC BY-NC V4.0, Open Access
Editorial
Predictive power of statistical significance
World journal of methodology, Vol.7(4), pp.112-116
12/26/2017
PMID: 29354483
Abstract
A statistically significant research finding should not be defined as a -value of 0.05 or less, because this definition does not take into account study power. Statistical significance was originally defined by Fisher RA as a -value of 0.05 or less. According to Fisher, any finding that is likely to occur by random variation no more than 1 in 20 times is considered significant. Neyman J and Pearson ES subsequently argued that Fisher's definition was incomplete. They proposed that statistical significance could only be determined by analyzing the chance of incorrectly considering a study finding was significant (a Type I error) or incorrectly considering a study finding was insignificant (a Type II error). Their definition of statistical significance is also incomplete because the error rates are considered separately, not together. A better definition of statistical significance is the positive predictive value of a -value, which is equal to the power divided by the sum of power and the -value. This definition is more complete and relevant than Fisher's or Neyman-Peason's definitions, because it takes into account both concepts of statistical significance. Using this definition, a statistically significant finding requires a -value of 0.05 or less when the power is at least 95%, and a -value of 0.032 or less when the power is 60%. To achieve statistical significance, -values must be adjusted downward as the study power decreases.
Metrics
3 Record Views
Details
- Title
- Predictive power of statistical significance
- Creators
- Thomas F Heston - Washington State University, Elson S. Floyd College of MedicineJackson M King - Creative Research Enterprises
- Publication Details
- World journal of methodology, Vol.7(4), pp.112-116
- Academic Unit
- Elson S. Floyd College of Medicine
- Identifiers
- 99901107739701842
- Language
- English
- Resource Type
- Editorial