On the Inhomogeneity of a Test Compounded of Two Rasch Homogeneous Subscales
Anton K. Formann, Ilse Rop · Psychometrika · 1987
Van den Wollenberg stated a theorem specifying the conditions for a test, which is composed of two Rasch homogeneous subscales, as also behaving Rasch homogeneously. In our note, simple numerical counterexamples are given for which this theorem fails.