Intellectual assessment is central to the process of diagnosing an intellectual disability and the assessment process needs to be valid and reliable. One fundamental aspect of validity is that of measurement invariance, i.e. that the assessment measures the same thing in different populations. There are reasons to believe that measurement…

A meta-analysis of the stability of low IQ (IQ less than 80) was performed on IQ tests that have been commonly used--tests that were derived by D. Wechsler (1949, 1955, 1974, 1981, 1991, 1997) and those based on the Binet scales (L. M. Terman, 1960; L. M. Terman & Merrill, 1972). Weighted-mean stability coefficients of 0.77 and 0.78 were found…

Estimates of the validity of random short forms can serve as benchmarks against which to appraise the validity of particular short forms. Formulas are presented for estimating the validity of random short forms and illustrated with Wechsler Adult Intelligence Scale-Revised (WAIS-R) and Minnesota Multiphasic Personality Inventory data. (Author/CM)

Reviews research on ability testing for adults with visual impairments, especially the tests used for vocational assessment and counseling. The verbal scales of the Wechsler Adult Intelligence Scale-Revised were found to be widely accepted. The problems, however, with relying solely on verbal assessment are addressed, and the need for tests for…