This severity continuum also demonstrated an expected pattern of convergent and discriminant validity with a host of concurrent variables, although, as with similar representations of alcohol use severity used previously in Project MATCH, it was limited in its ability to predict treatment outcome either as a main effect or in its interaction with treatment condition. Furthermore, it had limited ability to increment explained variance in validating variables once alcohol dependence and involvement scores were controlled. Three exceptions are worth noting: alcohol trait severity incremented additive markers in relation to AA involvement, social functioning and readiness for change. As these variables are potentially important for treatment-related decisions, this may suggest some promise for the IRT-derived continuum to augment more simple additive indications of alcohol severity in treatment planning, a possibility that merits additional research.
