This article presents a review of the "Wechsler Adult Intelligence Scale-Fourth Edition" (WAIS-IV), an individually administered measure of cognitive ability for individuals aged 16 years, 0 months to 90 years, 11 months. The WAIS-IV was designed with a number of specific goals including updated norms, increased user friendliness,…

A model-fitting analysis of the covariance structure of an intelligence quotient (IQ) data set is reported using a model that considers additive and nonadditive genetic parameters and shared and nonshared environment parameters that permit different estimates for different types of relatives. The use of LISREL for such purposes is reviewed. (SLD)