The analyses conducted in this study occurred in four stages: 1) establishment of an IRT-based dependence severity continuum and examination of its psychometric characteristics and relations to demographic variables, 2) examining the concurrent and incremental validity of that continuum, 3) scaling Project MATCH participants with regard to their placement (i.e., severity level) and fit (i.e., traitedness) to the empirically-developed severity continuum and 4) examining correlates of traitedness and the severity x traitedness interaction, including treatment response and differential outcome across treatments.
