On the ways of investigating the discriminant validity of a scale in giving special emphasis to estimation problems when investigating multitrait-multimethod matrices

Discriminant validity is a valuable property of psychological scales that is usually investigated in the framework of the multitrait-multimethod approach. The establishment of discriminant validity demands the demonstration that the scale of interest representing a specific construct is unrelated to scales representing other constructs. The original implementation of the multitrait-multimethod approach demands a large number of comparisons among the correlations of a multitraitmultimethod design. More recently discriminant validity is investigated by means of confirmatory factor models including latent variables for the representation of constructs and methods. The process of arriving at a decision concerning discriminant validity in investigating multitraitmultimethod data is described. Downsizing the complexity of the model and the usage of a ridge option are proposed and applied for overcoming the estimation problems that frequently obstruct confirmatory factor analysis of multitrait-multimethod data.