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This study was designed to assess the concurrent validity of the Shipley Institute of Living Scale (Shipley) with a criterion measure that measures fluid and crystallized abilities, the Kaufman Adult and Adolescent Intelligence Test (KAIT). Fifty-two undergraduate and graduate students were given the Shipley and the KAIT in counterbalanced order. The Shipley Total and KAIT Composite IQ scores were significantly correlated (r = .60). Evidence for convergent validity of Shipley Verbal and KAIT crystallized scores were provided by significant correlations between these measures (r = .66), while the Shipley Abstraction and KAIT crystallized subtests were not significantly correlated (r = .23). Similarly, Shipley Abstraction and KAIT fluid scores showed evidence of convergent validity as evidenced by significant correlations between the scores on the two tests (r = .57) while Shipley Verbal and KAIT fluid scores were not significantly correlated (r = .23). The results support the use of the Shipley as a brief measure of fluid and crystallized intelligence.
Developed over six decades ago, the Shipley Institute of Living Scale (Shipley, 1967; Zachary, 1991) is a brief measure of intelligence consisting of two subtests. On the Abstraction subtest, participants must complete numerical problems, word patterns, and analogies for 20 different problems, and on the Verbal subtest, participants must choose synonyms for 40 English words that become increasingly more difficult. The test usually takes less than 20 minutes to administer and yields raw scores that can be converted to standard IQ scores (Zachary, 1991).
While the Shipley enjoys status as a well-established brief measure of intelligence, the test was not developed from a theoretically based model of intelligence. The Abstraction and Verbal subtests of the Shipley, however, appear to measure constructs similar to the fluid and crystallized abilities first purported by Horn and Cattell (Cattell, 1941, 1963; Horn & Cattell, 1966) and later by Carroll and other researchers (Carroll, 1993; Horn & Noll, 1997). Indeed, the Shipley manual (Zachary, 1991) describes the Abstraction scale as tapping attention and problem solving processes that are more fluid in nature, while the Shipley Verbal scale is easily conceptualized as a test of crystallized ability due to its verbal content. Although the psychometric properties of the Shipley have been supported by research, the fact remains that the Shipley does...