Testing 40 predictions from the transtheoretical model.

Sensitive measurement of behavior change requires dependent measures that are sensitive to the whole spectrum of change, not just a single aspect of change. Traditional outcome variables such as point prevalence for smoking cessation focus on a single discrete event and ignore all other progress. Alternatively, the criterion measurement model (CMM) is an approach that posits a three-construct outcome model (habit strength, positive evaluation strength, and negative evaluation strength), where different constructs are sensitive to change for different aspects of the temporal domain. In this article, a series of 40 differential a priori predictions were tested using a large representative sample of smokers. The focus was on the prediction of specific effect sizes rather than statistical significance. A series of comparisons involving stage transitions was examined using five variables representing the three CMM constructs. The predictions involved movement from one of three initial stages (precontemplation, contemplation, and preparation) to stage membership 12 months later. Thirty-six of the 40 predictions were confirmed, indicating that the outcome model has strong construct validity and accurately reflects movement between the stages of change.