Overcoming Problems in Confirmatory Factor Analyses of MTMM Data: The Correlated Uniqueness Model and Factorial Invariance.

The general model typically used in the confirmatory factor analysis (CFA) approach to multitrait-multimethod (MTMM) data is plagued with methodological problems and frequently results in improper or unstable solutions. Here we reanalyze data from a previously published study, demonstrating that this model may lead to inappropriate interpretations even when it does converge to a proper solution, and describe safeguards against this occurrence. The results support the correlated uniqueness model, diagnostic tests of the validity of CFA-MTMM solutions, the inclusion of external validity criteria in the MTMM design as described by Marsh (1988; 1989; Marsh & Bailey, 19911, and the application of factorial invariance to test the stability of CFA-MTMM solutions. More generally, we demonstrate the flexibility of the CFA-MTMM approach for testing a variety of construct validity issues.