Factor structure of the WAIS-R by educational level: an examination of elderly persons.

A factor analysis of the WAIS-R by educational level for persons 75 years and older was conducted. Two- and three-factor solutions were generated for persons with 0 to 11 years of education and for high school graduates. A two-factor solution composed of verbal and perceptual-organization factors best explained the WAIS-R scores for subjects with 11 or fewer years of education. However, a three-factor solution emerged for persons with 12 or more years of schooling and consisted of the verbal comprehension, perceptual-organization, and freedom from distractibility factors. Clinicians must be aware of the potentially different factor structures generated by educational level to provide the most accurate interpretation of WAIS-R scores for elderly persons.