Commentary on Loring and Larrabee's Reanalysis of Reitan's Original Studies.

The article by Loring and Larrabee (2006) used effect size to compare Reitan's original Halstead Index (HI) data with Wechsler Bellevue Intelligence Scale (W-B) data. The results may be interpreted to support the concept that Halstead's concept of "biological" and "psychometric" intelligence was a form of "fluid" and "crystallized" intelligence. Except for three unused subtests, HI tests were fluid, while W-B performance tests were somewhat fluid and the W-B verbal tests were crystallized. Thus, the mean effect size of the normally used HI tests was almost twice that of W-B tests' mean size. The fluid nature of the HI tests provides their sensitivity to brain damage.