The Transtheoretical Model (TTM)

Consider the journey involved in adopting a regular exercise routine. Initially, you might reflect on how exercising could improve your well-being. You then take practical steps, perhaps signing up for a gym membership and buying some new workout clothes. Eventually, you head to the gym and keep it up for several weeks. 

As life gets busy, you worry about maintaining this new behavior and decide to recruit a gym buddy for some additional motivation. In the process of picking up a regular exercise behavior, you’ve moved through several stages of change—from contemplation and preparation to action and maintenance.

The TTM, also called the stages of change model, illustrates how people move through different levels of motivation, commitment, and action when attempting to alter or adopt a behavior.¹ The model was originally developed to understand why some people could manage behavior change more easily than others, suggesting that people have to be ready in order to enact change.

The TTM is often used in the context of lifestyle behaviors like nutrition, exercise, substance use, and stress management. People don’t change these behaviors overnight—rather, change is a lengthy, ongoing process that involves several distinct stages.

The TTM outlines six main stages of change that describe an individual’s preparedness for change.1,2 These are:

1. Precontemplation: People in this stage have no intention of making a change in the foreseeable future (within the next six months). They do not see a problem and lack awareness of the negative consequences of their behavior.
2. Contemplation: Individuals in this stage are aware that a problem exists and have started thinking about making a change in the near future (within the next six months). They recognize that their behavior is problematic, but have not yet made a commitment to take action.
3. Preparation: This stage is where intention and action come together. People in the preparation stage are aware that their behavior is problematic and that change would be beneficial. They start taking small steps to prepare for change and intend to take action immenently (within the next 30 days).
4. Action: This is the stage where change finally happens. Individuals in this stage modify their behavior or environment to overcome problems and intend to keep moving forward with the change.
5. Maintenance: People reach this stage once they have maintained the behavior for at least six months. They work to prevent relapse and consolidate gains to focus on the progress they have made. This stage has no limit—many people remain in the maintenance stage indefinitely.
6. Termination: The stage in which people have no desire to return to previous behavior and experience zero temptation for relapse. Most people never reach this stage, so it’s often excluded in health promotion programs.

Importantly, this is not a linear path, but cyclical. People can revert to earlier stages from any stage. For instance, someone who has been steadily going to the gym for several months might miss a few workouts and eventually stop exercising altogether, returning to the contemplation stage before moving forward again.

The primary goal of the TTM is to facilitate behavior change by identifying an individual’s readiness to change and providing tailored interventions that support their progression through the stages.

In addition to the six stages of change, there are three other components to the TTM: decisional balance, self-efficacy, and the processes of change.² Here’s a quick breakdown of each element:

Decisional Balance: The process of weighing the pros and cons of changing behavior. As people progress through the stages of change, the advantages of changing increasingly outweigh the disadvantages. For example, picking up an exercise routine might seem initially difficult due to factors like time constraints and physical discomfort. But as you progress, you’ll likely give more weight to the long-term health benefits of exercise than these short-term drawbacks.

Self-Efficacy: The level of confidence one has in their ability to make a positive change and overcome the temptation to relapse towards unhealthy behavior. Our self-efficacy tends to start low and grow as we progress through the stages of change. For example, once you’ve been maintaining a regular workout routine for several months, you’re likely to feel more confident in your ability to maintain it moving forward, despite whatever hurdles pop up in the future.

Processes of Change: The strategies or activities people use to progress forward, including both cognitive processes and overt activities.^1,3 Health researchers have added several processes of change to the TTM over the years, but the following 10 are fundamental to the model:

1. Consciousness Raising: Increasing one’s awareness about the healthy behavior through education and feedback.
2. Dramatic Relief: Paying attention to one’s emotions about the behavior and its consequences.
3. Self-Reevaluation: Realizing the healthy behavior aligns with one’s personal values.
4. Environmental Reevaluation: Noticing how the behavior affects others.
5. Social Liberation: Noticing that society supports the healthy behavior.
6. Self-Liberation: Believing in one’s ability to make the behavior change.
7. Helping Relationships: Seeking support from others.
8. Counterconditioning: Replacing unhealthy thoughts and behaviors with healthy substitutes.
9. Reinforcement Management: Rewarding the healthy behavior and reducing the rewards that come with the unhealthy behavior.
10. Stimulus Control: managing one’s environment to support the healthy behavior and remove triggers or cues that encourage the unhealthy behavior.

These processes of change roughly align with the stages of change. For example, people in the precontemplation and contemplation stages often rely on ‘consciousness raising’ and ‘dramatic relief' while those in the action and maintenance stages rely on ‘reinforcement management’ and ‘stimulus control.’

Psychologists James O. Prochaska and Carlo DiClemente developed the TTM in the late 1970s as part of their research on smoking cessation.1 Their goal was to understand why some smokers were able to quit on their own while others required further treatment. Their research led to the development of the TTM based on a comparative analysis of different theories of psychotherapy and behavior change—hence the name, transtheoretical model. 

Prochaska and DiClemente’s theoretical analysis revealed 10 processes that play a role in behavior change.⁴ To explore this theoretical concept, they conducted a study on smokers and found that these 10 processes of change could predict successful quitting. Their findings also revealed that behavior change unfolded through a series of six stages.

While initial research on the TTM focused on smoking cessation, the model was soon expanded to address other behaviors, including eating disorders, depression prevention, and substance use. Researchers found that behavior interventions were more effective when they were tailored to each individual’s stage of change.

Other theories were eventually integrated into the model. The concept of decisional balance was derived from Irving Janis and Leon Mann’s decision-making model while the concept of self-efficacy came from Albert Bandura’s theory of motivation and human agency. 

The TTM gained greater attention with the release of the book Changing for Good in 1994 by Prochaska, DiClemente, and colleague John Norcross. This book summarized research on the model and presented case studies to highlight the applications of the TTM for changing bad habits, giving readers practical insights into the use of TTM.⁴

James O. Prochaska: A prominent psychologist best known for developing the TTM. Prochaska published over 400 articles, many focusing on understanding and facilitating behavior change.⁵ He also authored several books on the TTM and its applications in the adoption of health-related behaviors like smoking cessation and addiction treatment.

Carlo DiClemente: A renowned psychologist who has made significant contributions to the field of addiction treatment and behavior change.⁶ DiClemente is credited with developing the TTM alongside Prochaska and has received several awards for his work. His research centers on behavior change and motivation, particularly around health-related behaviors.

The TTM is one of the most widely used models for understanding behavior change. It has been applied to numerous behaviors beyond smoking cessation and continues to inform behavior intervention strategies across various disciplines, from medication adherence to organizational change.¹

One of the most valuable contributions of the model is the idea that behavior change is a cyclical process rather than a one-time event. This has advanced our understanding of behavior change and led to the development of tailored intervention strategies that target people based on their stage of change, as opposed to one-size-fits-all interventions.

Public Health

This tailored approach is incredibly valuable for shaping public health initiatives. Research indicates that the TTM has applications for changing health behavior and preventing chronic disease by providing stage-based guidance to individuals. For example, one study found that TTM-based interventions on osteoporosis patients led to improved knowledge about increasing calcium levels, which is crucial to managing bone health.⁷

Organizational Change

Researchers have also explored using the TTM to support organizational change. James Prochaska’s wife, Janice Prochaska, shares some research in this area to highlight the applications of TTM in the workplace.⁸ She cautions that employees at higher levels of organizations tend to be further along the stages of change than those at lower levels. When people in higher positions are ready to make a change, they often impose changes on lower-level employees who may not be ready to take action, which can lead to resistance and other implementation challenges.

Leaders may have an easier time supporting and coordinating organizational change by applying the TTM. For example, one study explored the use of stage-dependent interventions to reduce musculoskeletal disorders in employees.8 Researchers found that employees varied widely in their readiness to change, but providing advice tailored to each individual’s stage of change was successful in helping employees make work activity changes that resulted in pain reduction.

The TTM has several limitations that should be considered when using this theory in the promotion of public health or organizational change.

For example, the theory ignores the broader social context in which change occurs—such as socioeconomic status and income—which can impact people’s ability to make behavioral changes.¹ The model also assumes that people logically plan out their behavior changes, but decision-making is often skewed away from rationality by emotions, cognitive biases, and external pressures.

These drawbacks may explain why research on the TTM yields inconsistent results. While many studies show that interventions based on the TTM can support behavior change, it’s not clear whether these interventions are more effective than other behavioral change models or standard intervention methods.7,9 For instance, one study found that TTM was just as effective as motivational interviewing at producing behavior change to address health risks such as inactivity, stress, and smoking.¹¹

In a large review of 23 randomized controlled trials, researchers determined that stage-based interventions are no more effective than non-stage-based interventions in changing smoking behavior.¹⁰  Notably, the authors suggested these findings could be due to the misuse of the model rather than the model itself—stage-based interventions are often applied incorrectly or inadequately. The effectiveness of any stage-based intervention depends on accurately classifying someone’s stage of change, but only two of the reviewed studies used a validated instrument to measure this.

At the same time, critics are quick to point out problems with classifying people into stages, many arguing the stages of change are overly arbitrary.¹ There are no set criteria to determine which stage of change someone is in, which may account for some of the inconsistencies in research results.

Changing human behavior is key to environmental conservation and sustainability. Zoos and aquariums offer an important avenue for educating the public and facilitating pro-environment behavior change, and tailoring programming to visitors’ stages of change might make these efforts more effective.

In a 2022 paper, researchers presented several examples of TTM applications in zoos.¹² For example, they pointed to a 2004 study at Disney's Animal Kingdom where visitors were categorized based on their stage of change. Researchers measured the visitors’ intention to change behavior before and after their visit, finding minimal change overall. Most of these zoo visitors were already in the preparation stage, but the educational materials better suited those in the precontemplation or contemplation stages.

As found at Disney's Animal Kingdom, most zoo programming falls under consciousness raising—this is best at moving people through the early stages of change but less useful at later stages. People preparing to make a pro-environment behavior change are unlikely to be swayed by information about habitat loss or ocean plastic. Instead, visitors at later stages of change may benefit from hands-on workshops where they can learn sustainable practices or opportunities to participate in community conservation projects.

Researchers suggest a simple survey to determine zoo visitors’ stages of change for specific behaviors. Using this survey data, zoos can identify targeted intervention strategies and reveal behaviors people are already doing. For instance, 80% of American and Canadian cat owners already keep their feline friends indoors, so targeting this bird-conservation behavior may not be productive.¹³ With this information, zoo staff can focus on maintaining behaviors or shift to behaviors where visitors are in earlier stages of change, potentially having a greater impact on conservation efforts.

The Stages of Change: How to Motivate, Facilitate, and Reinforce Desired Behaviors

Stage-based models of behavior change, like the TTM, involve various transition phases and processes that explain how people progress toward change. In general, these models suggest that people move between phases through a process of motivation, facilitation, and reinforcement. Check out this article to learn more about these intervention strategies.

The COM-B Model for Behavior Change

The COM-B model proposes that capability, opportunity, and motivation are key factors in modifying behavior. Similar to the TTM, the COM-B model focuses on tailoring interventions to people’s readiness to change. Take a look at this article to learn about the COM-B model and how it has been applied to improve adherence to hearing-aid use, antibiotics, and COVID-19 guidelines.

1. The Transtheoretical Model (Stages of Change). (2022, November 3). sph.bu.edu. Retrieved July 23, 2024, from https://sphweb.bumc.bu.edu/otlt/mph-modules/sb/behavioralchangetheories/behavioralchangetheories6.html
2. Raihan, N., & Cogburn, M. (2023). Stages of Change Theory. In StatPearls (Updated March 6, 2023). Treasure Island, FL: StatPearls Publishing. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK556005/
3. Prochaska, J. O., & Velicer, W. F. (1997). The Transtheoretical Model of Health Behavior Change. American Journal of Health Promotion : AJHP, 12(1), 38–48. https://doi.org/10.4278/0890-1171-12.1.38 
4. Craig, Shelley L. , & D'Souza, Sandra (2018). Transtheoretical Model of Change. obo in Social Work. doi: 10.1093/obo/9780195389678-0268
5. University saddened by loss of Professor Emeritus James O. Prochaska. (2023, July 17). The University of Rhode Island. Retrieved July 23, 2024, from https://www.uri.edu/news/2023/07/university-saddened-by-loss-of-professor-emeritus-james-o-prochaska/
6. Carlo DiClemente, Ph.D. ABPP. (n.d.). The University of Texas at Austin. Retrieved July 23, 2024, from https://sites.utexas.edu/hbrt/about-us/our-team/carlo-diclemente-ph-d-abpp/
7. Hashemzadeh, M., Rahimi, A., Zare-Farashbandi, F., Alavi-Naeini, A. M., & Daei, A. (2019). Transtheoretical Model of Health Behavioral Change: A Systematic Review. Iranian Journal of Nursing and Midwifery Research, 24(2), 83–90. https://doi.org/10.4103/ijnmr.IJNMR_94_17
8. Prochaska, J. M. (2007). The Transtheoretical Model applied to the community and the workplace. Journal of Health Psychology, 12(1), 198–200. doi: 10.1177/1359105307071754
9. Levesque, D. A., Van Marter, D. F., Schneider, R. J., Bauer, M. R., Goldberg, D. N., Prochaska, J. O., & Prochaska, J. M. (2011). Randomized Trial of a Computer-Tailored Intervention for Patients with Depression. American Journal of Health Promotion, 26(2), 77-89 https://doi.org/10.4278/ajhp.090123-QUAN-27
10. Riemsma, R. P., Pattenden, J., Bridle, C., Sowden, A. J., Mather, L., Watt, I. S., et al. (2003). Systematic review of the effectiveness of stage-based interventions to promote smoking cessation. BMJ, 326, 1175. https://doi.org/10.1136/bmj.326.7400.1175 
11. Prochaska, J. O., Butterworth, S., Redding, C. A., Burden, V., Perrin, N., Leo, M., Flaherty-Robb, M., & Prochaska, J. M. (2008). Initial efficacy of MI, TTM tailoring and HRI’s with multiple behaviors for employee health promotion. Preventive Medicine, 46(3), 226-231. https://doi.org/10.1016/j.ypmed.2007.11.007 
12. Abrash Walton, A., Nageotte, N. L., Heimlich, J. E., & Threadgill, A. V. (2022). Facilitating behavior change: Introducing the Transtheoretical Model of Behavior Change as a conservation psychology framework and tool for practitioners. Zoo biology, 41(5), 386–397. https://doi.org/10.1002/zoo.21704
13. Foreman-Worsley, R., Finka, L. R., Ward, S. J., & Farnworth, M. J. (2021). Indoors or Outdoors? An International Exploration of Owner Demographics and Decision Making Associated with Lifestyle of Pet Cats. Animals : an open access journal from MDPI, 11(2), 253. https://doi.org/10.3390/ani11020253