Brief Notes: Statistical Power Analysis and Research Results

I was most pleased by the recent publication by Brewer, “On the Power of Statistical Tests in the American Educational Research Journal” 1972, and understandably delighted with his heavy reliance, in accomplishing his survey, on my power handbook ( Cohen, 1969 ). I strongly agree with his stress on the importance of power analysis. Further, his survey’s confirmation of my finding of a decade ago ( Cohen, 1962 ; 1965 ) that the neglect of power analysis results in generally low power is very useful, although not surprising. Unfortunately, however, some conceptual errors in the article may seriously mislead educational researchers, and undermine our shared goal of promulgating power analysis. Hence, this note.