A CRITERION MEASUREMENT MODEL FOR HEALTH BEHAVIOR-CHANGE

Researchers in the field of health behavior change have traditionally relied on a univariate criterion measure to evaluate the efficacy of a n intervention. Such measures have superficial face validity but suffe r from a number of problems: (a) lack of precise definitions; (b) poor statistical power; and (c) a lack of meaningfulness for some aspects of the problem. As an alternative, a theoretical model is developed th at attempts to define more appropriate multivariate sets of dependent variables for the study of health behavior change. The model involves three separate constructs: Positive Evaluation Strength, Negative Eval uation Strength, and Habit Strength. The pattern of change for each co nstruct is described across four stages of change: Precontemplation, C ontemplation, Action, and Maintenance. For each construct, two thresho lds are proposed representing the ability of the environment to modify the construct. Four tests of the model are provided from existing dat a sets. First, a structural model analysis was used to test if the pro posed measurement model adequately fits the data. Second, a dynamic ty pology approach produced profiles of change that are consistent with t he model. Third, a time series analysis provided support for the assum ed model. Fourth, longitudinal, five-wave panel design was employed to test if the relation between the two cognitive variables (Pros and Co ns) and the behavioral measure (Habit Strength) was consistent with th e model. Implications for alternative intervention strategies are disc ussed.