The transtheoretical model of behaviour change: Are the stages qualitatively different?

intention to stop smoking was studied by applying the stage variable from the transtheoretical model and a traditional "continuous" 7-point intention measure. Four hundred and Twenty one respondents, representative of Norwegian daily smokers aged 16-79, comprised the sample for the study. As expected, the pros of smoking outweighed the cons in precontemplation, while the cons of smoking outweighed the pros in the preparation stage. Furthermore, the hypothesised contrasts for cons between stages were empirically supported, while those for cessation related confidence and pros of smoking were not. These findings can be interpreted as providing partial support for the idea of qualitatively different stages. However, all the criterion variables were also linearly associated with the 7-point intention measure. Further analysis showed that including the continuous intention measure in a regression model after the inclusion of stage increased the prediction of three criterion variables, while no gain in information was observed when stage was included in the model after intention. Thus a "continuous" intention measure may provide more detailed information than a three-category stage variable, and the data might just as well have been interpreted as supporting the notion of a continuous intention measure.