APA Dictionary of Psychology

a matrix showing correlations among two or more measurement techniques used to assess two or more constructs or traits, as obtained from a multitrait–multimethod model. It includes correlations among the same traits with different methods (i.e., monotrait–heteromethod) and among different traits with the same method (i.e., heterotrait–monomethod). The former are expected to be the largest, thus demonstrating convergent validity, whereas the latter are expected to be smallest, demonstrating discriminant validity.