Abstract
Failure to consider statistical power when achieving apparently "negative" results prevents accurate interpretation of the results. A nonsignificant result can be obtained when one includes an insufficient number of subjects to permit observation of a true effect (low power to detect an effect), or when one has an adequate number of subjects, but a meaningful effect does not exist (high power, no effect); one can also have a situation of lower power and no real effect. Without considering power, one is unable to distinguish a "negative" experiment from an inadequate one. This article examines 154 published nonsignificant t-test results. When power is calculated with an effect size equal to a standardized difference of unity, over 50% of the tests have inadequate power.
Original language | English (US) |
---|---|
Pages (from-to) | 295-299 |
Number of pages | 5 |
Journal | Psychiatry research |
Volume | 23 |
Issue number | 3 |
DOIs | |
State | Published - Mar 1988 |
Externally published | Yes |
Keywords
- Statistical methods
- Type II error
- power
ASJC Scopus subject areas
- Psychiatry and Mental health
- Biological Psychiatry