The primary objective underlying the development of the tests described in this chapter was to provide clinicians with better and more comprehensive procedures for investigating problems of cognition and learning. The Woodcock—Johnson Tests of Cognitive Ability—Revised (WJ—R COG) (Woodcock & Johnson, 1989) approaches this goal in two ways. First, the WJ—R COG provides a broader array of information about factors that may be related to learning problems than is available through the use of any other single instrument. Second, certain interpretive procedures are especially useful for evaluating the significance and implications of obtained information. Because of these unique features, both the 1977 (Woodcock & Johnson, 1977) and the 1989 WJ—R have been widely used in school and clinical settings for the diagnosis of learning and reading disabilities (Ostertag & Baker, 1984; Dalke, 1988; Cuenin, 1990; Lewis, 1990).

The WJ—R COG is a wide-age-range, comprehensive set of individually administered tests for measuring cognitive abilities, scholastic aptitudes, and oral language that is complemented by the fully co-normed Woodcock—Johnson Tests of Achievement—Revised (WJ—R ACH) (Woodcock & Johnson, 1989).