Estimation problems in the block-diagonal model of the multitrait-multimethod matrix

Abstract

The most popular method used to analyze the multitrait-multimethod (MTMM) matrix has been confirmatory factor analysis (CFA). The block-diagonal model, in which trait effects, trait correlations, method effects, and method correlations are simultaneously estimated is examined in detail. Analysis of published data from 18 correlation matrices showed estimation problems in all but one case. Simulations were used to show how identification and specification difficulties may account for these problems. Even trivial misspecification of a single parameter can prevent program convergence. These problems render the CFA block-diagonal approach to analyzing MTMM data less useful than has generally been thought. Index terms: construct validity, covariance structure modeling, factor analysis, multitrait-multimethod matrix, parameter estimation in confirmatory factor analysis.