Prediction of WAIS IQ with the National Adult Reading Test: Cross‐validation and extension

Abstract

Nelson (1982) presented regression equations for the prediction of Wechsler Adult Intelligence Scale (WAIS) IQ from performance on the National Adult Reading Test (NART). In a cross‐validation sample ( n = 151) these equations predicted 66, 72 and 33 per cent of the variance in WAIS Full Scale, Verbal and Performance IQ respectively. There were no ceiling or floor effects in the relationship between NART performance and WAIS IQ despite the wide IQ range of the sample. The standardization and cross‐validation samples were combined ( n = 271) to generate new regression equations. These equations should be used in preference to the original equations as they are based on a larger sample with a wider IQ and age range. Combining NART and Schonell Graded Word Reading Test errors did not improve IQ prediction in poor readers. A detailed examination of the NART's test—retest and inter‐rater reliability was also conducted.