Analysis of the multitrait-multimethod matrix by confirmatory factor analysis.

The multitrait-multimethod (MTMM) matrix permits examination of the convergent and discriminant validity of psychological measures. Estimation using confirmatory factor analysis (CFA), the predominant analytical technique, has often resulted in severe difficulties, such as out-of-range estimates and convergence problems. This article shows that an important special case of one of the more frequently advocated CFA models is not identified and is therefore not estimable. Because most MTMM data are likely to conform closely to this special case, resulting analyses suffer from empirical underidentification. Alternaive CFA models are discussed