The quest for "power": contradictory hypotheses and inflated sample sizes.
To have the "power" of avoiding undersized clinical trials, the customary statistical strategy used in the past few decades is aimed at rejecting both a null stochastic hypothesis and a contradictory alternative hypothesis. This approach gives a trial the "power" to confirm the "insignificance" of differences much smaller than the large value of delta desired in trials done to show efficacy. In many instances, however, a prime problem is that the current "double-significance" approach produces sample sizes 2-3 times larger than needed for stochastic confirmation of large differences (> or =delta). The inflated sample sizes and consequent problems can be avoided if a realistic value for delta is chosen and maintained thereafter, and if an adequate "capacity" is calculated for "single significance."
Feinstein
A R
AR
Department of Medicine, Yale University School of Medicine, New Haven, Connecticut 06510, USA.
Concato
J
J
D015982:Bias; D002986:Clinical Trials as Topic / Q000592:standards*; D016001:Confidence Intervals; D003627:Data Interpretation, Statistical; D015203:Reproducibility of Results; D018401:Sample Size; D013269:Stochastic Processes