On the value of homogeneous constructs for construct validation, theory testing, and the description of psychopathology

Abstract

The authors argue for a significant shift in how clinical psychology researchers conduct construct validation and theory validation tests. They argue that sound theory and validation tests can best be conducted on measures of unidimensional or homogeneous constructs. Hierarchical organizations of such constructs are useful descriptively and theoretically, but higher order composites do not refer to definable psychological processes. Application of this perspective to the approach of the Diagnostic and Statistical Manual of Mental Disorders to describing psychopathology calls into doubt the traditional use of the syndromal approach, in which single scores reflect the presence of multidimensional disorders. For many forms of psychological dysfunction, this approach does not appear optimal and may need to be discarded. The authors note that their perspective represents a straightforward application of existing psychometric theory, they demonstrate the practical value of adopting this perspective, and they provide evidence that this shift is already under way among clinical researchers. Description in terms of homogeneous dimensions provides improved validity, utility, and parsimony. In contrast, the use of composite diagnoses can retard scientific progress and hamper clinicians' efforts to understand and treat dysfunction.

Figure 1

A depiction of one hierarchical organization of personality constructs. At the highest level are alpha and beta, at the next level are the five factors of the Big Five model of personality, and at the lowest level are the 30 specific trait or facet scales (six scales per factor; for simplicity's sake, we have not labeled each of the 30 facets). A = Agreeableness; C = Conscientiousness; N = Neuroticism; E = Extraversion; O = Openness to Experience.