On the Relationship Between Validity and Power

This article examines the relationship between predictive validity and statistical power. It is shown that higher validity may be associated with scales exhibiting lower power, whereas higher power may be warranted for scales possessing lower validity. High validity is in general neither a necessary nor sufficient condition for high power with scales contemplated for use as dependent variables in social science research. Conversely, high power is neither necessary nor sufficient for high validity. A numerical example illustrates this interrelation.