It follows that when we refer to construct validity studies, we are necessarily referring to simultaneous tests of psychological theories and of psychological measures (Cronbach & Meehl, 1955; Smith, 2005). The process of construct validation requires clear, coherent definitions of target constructs and a clear statement of anticipated relationships between the target construct and other constructs. Tests of the validity of construct measures must inevitably be tests of theories specifying relationships among the constructs. A key point for the present discussion is this: To the degree that one uses a single score from a target measure that includes multiple dimensions (such as a measure of posttraumatic stress disorder thought to include four factors, or a measure of extraversion thought to have six facets), one's construct validation/theory test has theoretical uncertainty built in. Such a test is likely to have reduced scientific value.
