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 (pre-contemplation, 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. (C) 1999 Elsevier Science Ltd.