A procedure for examining essential unidimensionality in multicomponent measuring instruments is discussed. The method is based on an application of latent variable modeling and is concerned with the extent to which a common factor for all components of a given scale accounts for their correlations. The approach provides point and interval estimates of the proportion of observed measures interrelationships that is explained by the common factor, the proportion explained by possible additional factors, and of the difference in these two proportions. The procedure is readily used in empirical research using the popular software Mplus and is illustrated with a numerical example. (Contains 2 tables, 1 figure, and 5 notes.)