Does the Shipley Institute of Living Scale Measure Fluid and Crystallized Abilities?(Report‪)‬

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 not operate from an established theoretical base.