Latent Traits and the Possibility of Motion.

Points of agreement and disagreement with Maraun's (1996) account of factor indeterminacy are briefly stated. It is pointed out that if the common factor model must be discarded because of indeterminacy, so also must almost all the technology of psychological measurement, including the whole of item response theory. This unpalatable conclusion can be avoided by recognizing the behavior domain concept as the essential foundation of all theory for latent variables. Applications of behavior domain theory require a higher standard of psychological conceptualization than is commonly met by researchers.