PIP: The Transtheoretical Model of Behavior Change (TTM), originally developed by James Prochaska and his colleagues, addresses the psychological mechanisms of changing a health behavior. The primary tenet of the TTM is that people move through a series of stages on their way to making a change. The five Stages of Change based on TTM can be applied to various health behaviors, from condom use to smoking cessation to cancer screening. Assessing Stages of Change can be used to demonstrate the beneficial effects of sexuality education programs. These stages, which classify individuals according to their current behavior and their intentions for future behavior, are composed of the following: 1) precontemplation; 2) contemplation; 3) ready for action or preparation; 4) action; and 5) maintenance. Individuals may go through all these stages in a linear fashion, skip stages, or move back and forth between them. Furthermore, this model suggests that education programs should be dependent on the participant's stage of readiness to change and should target the individual's perceptions regarding the pros and cons of the behavior in question.