Statistical power of psychological research: What have we gained in 20 years?

Power was calculated for 6,155 statistical tests in 221 journal articles published in the 1982 volumes of the Journal of Abnormal Psychology, Journal of Consulting and Clinical Psychology, and Journal of Personality and Social Psychology. Power to detect small, medium, and large effects was .17, .57, and .83, respectively. 20 years after Cohen (1962) conducted the first power survey, the power of psychological research is still low. The...