Chunk #6 — Development and Heterotypic Continuity of Externalizing Problems — Ensuring conceptual equivalence for comparing scores on different 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 in the factor structure with age. Fifth, the measures should have high internal consistency. In sum, in order to model externalizing trajectories, it is important for measures to have theoretical relevance to the construct at each age examined and to be on a comparable metric for measurement equivalence (as opposed to measurement invariance, which is unnecessary in cases of heterotypic continuity; Knight & Zerr, 2010).
