LATENT TRANSITION ANALYSIS FOR LONGITUDINAL DATA

Assessing outcome is a critical problem for the study of addictive beh aviors. Traditional approaches often lack power and sensitivity. Laten t Transition Analysis is an alternative procedure that is applicable t o categorical latent variable models such as stage models. The method involves four different types of parameters, each of which may be rele vant to different research questions. Two examples that employ the Sta ges of Change construct are used to illustrate the method. In the firs t example, three different models of longitudinal change are compared. in the second example, the effects of an expert system intervention f or smoking is compared to a control condition. The method permits the investigation of a series of specific comparisons: (1) the effectivene ss of the intervention for individuals in different stages can be asse ssed; (2) the effectiveness of the intervention can be evaluated for d ifferent time intervals; and (3) the effects of intervention on both p rogression through the stages and regression through the stages or rel apse can be assessed. Other potential applications of the method are a lso discussed.