Individual-to-Group Profile Comparisons By rp: Elevation, Scatter, and Extreme Scores

Abstract

Profile matching is the subject of much methodological controversy, including the question of sensitivity of a profile similarity index to elevation and scatter. The tendency to extreme scores (TES) is a function of elevation and scatter, affecting sensitive indices, such as Cattell's rp, in such a way that a flat profile (low TES) will, in general, be found more similar to a standard than will an extreme profile (high TES). TES is an artifact when profile matching is used in clinical diagnosis. TES was found to account for 60% of the variance among rps to 118 criterion groups, with marked effects on individual subjects.