Chunk #5 — Development and Heterotypic Continuity of Externalizing Problems — Ensuring conceptual equivalence for comparing scores on different measures
POM rescaling approaches do not ensure, however, that variables at different ages are on the same conceptual metric. In order to ensure this, construct validity invariance is also necessary (Knight & Zerr, 2010). In other words, although identical measures over time are unnecessary, the measures should have identical meaning across the time frame of the study (Owens & Shaw, 2003). There are many ways to develop construct validity of a set of measures for a given construct. First, the items selected for the measures should be based on theory—they should be judged to reflect the same construct and the items should adequately sample the different facets of the construct (content or face validity). Second, despite heterotypic continuity in the long-term in the case of externalizing behavior, there should be short-term test-retest reliability of the measures across time. Third, the measures should show convergent validity with each other and discriminant validity with measures of distinct constructs. Fourth, the measures should demonstrate a similar factor structure across time, yet might not be expected to have an invariant structure because of qualitative changes
