Transtheoretical Model (TTM)

(also called Stages of Change)


People don’t change all at once. Instead, they go through a process that can begin before they have made any specific plans to change. The process ends with the change having been solidly established for more than six months, but there can be slips and relapses along the way. Moving audience members at the early stages of change (which involve more thinking) would involve different strategies than would moving them through later stages (which involve more doing).


Prochaska, J.O. & DiClemente, C.C.

Seminal references

Prochaska JO, DiClemente CC. Stages and processes of self-change of smoking: Toward an integrative model of change. Journal of Consulting and Clinical Psychology 51(3): 390–395, 1983.

Bandura A. Moral disengagement in the perpetration of inhumanities. Personality and Social Psychology Review, 1999, (3), 193-209.

Major constructs

Stages of readiness to change: precontemplation, contemplation, preparation, action, & maintenance. Associated with each stage is a list of “Processes of Change” – internal and external strategies for progressing through the stages. Decisional balance self-efficacy and temptation to relapse appear in the later writings.


Reger B, Cooper L, Booth-Butterfield S, Smith H, Bauman A, Wootan M, Middlestadt S, Marcus B, Greer F. Wheeling Walks: a community campaign using paid media to encourage walking among sedentary older adults. Prev Med. 2002 Sep;35(3):285-92. PubMed PMID: 12202072.

CDC AIDS Community Demonstration Projects Research Group. (1999). The CDC AIDS Community Demonstration Projects: A multi-site community-level intervention to promote HIV risk reduction. American Journal of Public Health, 89 (3), 336-345.

Major advantages

Major Criticisms


National Cancer Institute, Theory at a Glance (see pages 15-16)

Cancer Prevention Research Center, Transtheoretical Model