To develop a continuous or proportionate measure of stage of change using the Transtheoretical Model, one starts with the underlying premise that there is a concept called stage of change and that it is made up of unique constructs or stages that have been named Precontemplation, Contemplation, Preparation, Action, and Maintenance. You then have to flesh out a definition for each of those names. This starts with a focus group or by talking with people that you have staged with an algorithm. From the algorithm, you have the intentions of the early stage people and you know the behavior of the later staged subjects. What you want to learn is the missing half of the picture.