The transtheoretical model of behavior change is an integrative theory of therapy that assesses an individual's readiness to act on a new healthier behavior, and provides strategies, or processes of change to guide the individual.[1] The model is composed of constructs such as: stages of change, processes of change, levels of change, self-efficacy, and decisional balance.[1]
The transtheoretical model is also known by the abbreviation "TTM"[2] and sometimes by the term "stages of change",[3][4] although this latter term is a synecdoche since the stages of change are only one part of the model along with processes of change, levels of change, etc.[1][5] Several self-help books—Changing for Good (1994),[6] Changeology (2012),[7] and Changing to Thrive (2016)[8]—and articles in the news media[9][10][11][12][13] have discussed the model. It has been called "arguably the dominant model of health behaviour change, having received unprecedented research attention, yet it has simultaneously attracted criticism".[14]
This core construct "reflects the individual's relative weighing of the pros and cons of changing".[16][nb 5] Decision making was conceptualized by Janis and Mann as a "decisional balance sheet" of comparative potential gains and losses.[31] Decisional balance measures, the pros and the cons, have become critical constructs in the transtheoretical model. The pros and cons combine to form a decisional "balance sheet" of comparative potential gains and losses. The balance between the pros and cons varies depending on which stage of change the individual is in.
Sound decision making requires the consideration of the potential benefits (pros) and costs (cons) associated with a behavior's consequences. TTM research has found the following relationships between the pros, cons, and the stage of change across 48 behaviors and over 100 populations studied.
The evaluation of pros and cons is part of the formation of decisional balance. During the change process, individuals gradually increase the pros and decrease the cons forming a more positive balance towards the target behaviour. Attitudes are one of the core constructs explaining behaviour and behaviour change in various research domains.[33] Other behaviour models, such as the theory of planned beh This core construct "reflects the individual's relative weighing of the pros and cons of changing".[16][nb 5] Decision making was conceptualized by Janis and Mann as a "decisional balance sheet" of comparative potential gains and losses.[31] Decisional balance measures, the pros and the cons, have become critical constructs in the transtheoretical model. The pros and cons combine to form a decisional "balance sheet" of comparative potential gains and losses. The balance between the pros and cons varies depending on which stage of change the individual is in.
Sound decision making requires the consideration of the potential benefits (pros) and costs (cons) associated with a behavior's consequences. TTM research has found the following relationships between the pros, cons, and the stage of change across 48 behaviors and over 100 populations studied.
Due to the use of decisional balance and attitude, travel behaviour researchers have begun to combine the TTM with the TPB. Forward[36] uses the TPB variables to better differentiate the different stages. Especially all TPB va
Due to the use of decisional balance and attitude, travel behaviour researchers have begun to combine the TTM with the TPB. Forward[36] uses the TPB variables to better differentiate the different stages. Especially all TPB variables (attitude, perceived behaviour control, descriptive and subjective norm) are positively show a gradually increasing relationship to stage of change for bike commuting. As expected, intention or willingness to perform the behaviour increases by stage.[36] Similarly, Bamberg[35] uses various behavior models, including the transtheoretical model, theory of planned behavior and norm-activation model, to build the stage model of self-regulated behavior change (SSBC). Bamberg claims that his model is a solution to criticism raised towards the TTM.[35] Some researchers in travel, dietary, and environmental research have conducted empirical studies, showing that the SSBC might be a future path for TTM-based research.[35][37][38]
This core construct is "the situation-specific confidence people have that they can cope with high-risk situations without relapsing to their unhealthy or high risk-habit".[16][nb 6] The construct is based on Bandura's self-efficacy theory and conceptualizes a person's perceived ability to perform on a task as a mediator of performance on future tasks.[39][40] In his research Bandura already established that greater levels of perceived self-efficacy leads to greater changes in behavior.[40] Similarly, Ajzen mentions the similarity between the concepts of self-efficacy and perceived behavioral control.[41] This underlines the integrative nature of the transtheoretical model which combines various behavior theories. A change in the level of self-efficacy can predict a lasting change in behavior if there are adequate incentives and skills. The transtheoretical model employs an overall confidence score to assess an individual's self-efficacy. Situational temptations assess how tempted people are to engage in a problem behavior in a certain situation.
In one empirical study of psychotherapy discontinuation published in 1999, measures of levels of change did not predict premature discontinuation of therapy.[42] Nevertheless, in 2005 the creators of the TTM stated that it is important "that both therapists and clients agree as to which level they attribute the problem and at which level or levels they are willing to target as they work to change the problem behavior".[1]:152
Psychologist Donald Fromme, in his book Systems of Psychotherapy, adopted many ideas from the TTM, but in place of the levels of change construct, Fromme proposed a construct called contextual focus, a spectrum from physiological microcontext to environmental macrocontext: "The horizontal, contextual focus dimension resembles TTM's Levels of Change, but emphasizes the breadth of an intervention, rather than the latter's focus on intervention depth."[5]:57
The outcomes of the TTM computerized tailored interventions administered to participants in pre-Action stages are outlined below.
A national sample of pre-Action adults was provided a stress
Psychologist Donald Fromme, in his book Systems of Psychotherapy, adopted many ideas from the TTM, but in place of the levels of change construct, Fromme proposed a construct called contextual focus, a spectrum from physiological microcontext to environmental macrocontext: "The horizontal, contextual focus dimension resembles TTM's Levels of Change, but emphasizes the breadth of an intervention, rather than the latter's focus on intervention depth."[5]:57
The outcomes of the TTM computerized tailored interventions administered to participants in pre-Action stages are outlined below.
A nati
A national sample of pre-Action adults was provided a stress management intervention. At the 18-month follow-up, a significantly larger proportion of the treatment group (62%) was effectively managing their stress when compared to the control group. The intervention also produced statistically significant reductions in stress and depression and an increase in the use of stress management techniques when compared to the control group.[43] Two additional clinical trials of TTM programs by Prochaska et al. and Jordan et al. also found significantly larger proportions of treatment groups effectively managing stress when compared to control groups.[2][44]
Members of a large
Members of a large New England health plan and various employer groups who were prescribed a cholesterol lowering medication participated in an adherence to lipid-lowering drugs intervention. More than half of the intervention group (56%) who were previously pre-Action were adhering to their prescribed medication regimen at the 18-month follow-up. Additionally, only 15% of those in the intervention group who were already in Action or Maintenance relapsed into poor medication adherence compared to 45% of the controls. Further, participants who were at risk for physical activity and unhealthy diet were given only stage-based guidance. The treatment group doubled the control group in the percentage in Action or Maintenance at 18 months for physical activity (43%) and diet (25%).[46]
Participants were 350 primary car
Participants were 350 primary care patients experiencing at least mild depression but not involved in treatment or planning to seek treatment for depression in the next 30 days. Patients receiving the TTM intervention experienced significantly greater symptom reduction during the 9-month follow-up period. The intervention's largest effects were observed among patients with moderate or severe depression, and who were in the Precontemplation or Contemplation stage of change at baseline. For example, among patients in the Precontemplation or Contemplation stage, rates of reliable and clinically significant improvement in depression were 40% for treatment and 9% for control. Among patients with mild depression, or who were in the Action or Maintenance stage at baseline, the intervention helped prevent disease progression to Major Depression during the follow-up period.[47]
Five-hund
Five-hundred-and-seventy-seven overweight or moderately obese adults (BMI 25-39.9) were recruited nationally, primarily from large employers. Those randomly assigned to the treatment group received a stage-matched multiple behavior change guide and a series of tailored, individualized interventions for three health behaviors that are crucial to effective weight management: healthy eating (i.e., reducing calorie and dietary fat intake), moderate exercise, and managing emotional distress without eating. Up to three tailored reports (one per behavior) were delivered based on assessments conducted at four time points: baseline, 3, 6, and 9 months. All participants were followed up at 6, 12, and 24 months. Multiple Imputation was used to estimate missing data. Generalized Labor Estimating Equations (GLEE) were then used to examine differences between the treatment and comparison groups. At 24 months, those who were in a pre-Action stage for healthy eating at baseline and received treatment were significantly more likely to have reached Action or Maintenance than the comparison group (47.5% vs. 34.3%). The intervention also impacted a related, but untreated behavior: fruit and vegetable consumption. Over 48% of those in the treatment group in a pre-Action stage at baseline progressed to Action or Maintenance for eating at least 5 servings a day of fruit and vegetables as opposed to 39% of the comparison group. Individuals in the treatment group who were in a pre-Action stage for exercise at baseline were also significantly more likely to reach Action or Maintenance (44.9% vs. 38.1%). The treatment also had a significant effect on managing emotional distress without eating, with 49.7% of those in a pre-Action stage at baseline moving to Action or Maintenance versus 30.3% of the comparison group. The groups differed on weight lost at 24 months among those in a pre-Action stage for healthy eating and exercise at baseline. Among those in a pre-Action stage for both healthy eating and exercise at baseline, 30% of those randomized to the treatment group lost 5% or more of their body weight vs. 16.6% in the comparison group. Coaction of behavior change occurred and was much more pronounced in the treatment group with the treatment group losing significantly more than the comparison group. This study demonstrates the ability of TTM-based tailored feedback to improve healthy eating, exercise, managing emotional distress, and weight on a population basis. The treatment produced the highest population impact to date on multiple health risk behaviors.[48]
Multiple studies have found individualized interventions tailored on the 14 TTM variables for smoking cessation to effectively recruit and retain pre-Action participants and produce long-term abstinence rates within the range of 22% – 26%. These interventions have also consistently outperformed alternative interventions including best-in-class action-oriented self-help programs,[49] non-interactive manual-based programs, and other common interventions.[50][51] Furthermore, these interventions continued to move pre-Action participants to abstinence even after the program ended.[50][51][52] For a summary of smoking cessation clinical outcomes, see Velicer, Redding, Sun, & Prochaska, 2007 and Jordan, Evers, Spira, King & Lid, 2013.[44][53]
The use of TTM in travel behaviour interventions is rather novel. A number of cross-sectional studies investigated the individual constructs of TTM, e.g. stage of change, decisional balance and self-efficacy, with regards to transport mode choice. The cross-sectional studies identified both motivators and barriers at the different stages regarding biking, walking and public transport.[55][56]The use of TTM in travel behaviour interventions is rather novel. A number of cross-sectional studies investigated the individual constructs of TTM, e.g. stage of change, decisional balance and self-efficacy, with regards to transport mode choice. The cross-sectional studies identified both motivators and barriers at the different stages regarding biking, walking and public transport.[55][56][57][58] The motivators identified were e.g. liking to bike/walk, avoiding congestion and improved fitness. Perceived barriers were e.g. personal fitness, time and the weather. This knowledge was used to design interventions that would address attitudes and misconceptions to encourage an increased use of bikes and walking. These interventions aim at changing people's travel behaviour towards more sustainable and more active transport modes. In health-related studies, TTM is used to help people walk or bike more instead of using the car.[55][59][60][61][62][63] Most intervention studies aim to reduce car trips for commute to achieve the minimum recommended physical activity levels of 30 minutes per day.[55] Other intervention studies using TTM aim to encourage sustainable behaviour.[64][65][66] By reducing single occupied motor vehicle and replacing them with so called sustainable transport (public transport, car pooling, biking or walking), greenhouse gas emissions can be reduced considerably. A reduction in the number of cars on our roads solves other problems such as congestion, traffic noise and traffic accidents. By combining health and environment related purposes, the message becomes stronger. Additionally, by emphasising personal health, physical activity or even direct economic impact, people see a direct result from their changed behaviour, while saving the environment is a more general and effects are not directly noticeable.[67][58][68]
Different outcome measures were used to assess the effectiveness of the intervention. Health-centred intervention studies measured BMI, weight, waist circumference as well as general health. However, only one of three found a significant change in general health, while BMI and other measures had no effect.[55] Measures that are associated with both health and sustainability were more common. Effects were reported as number of car trips, distance travelled, main mode share etc. Results varied due to greatly differing approaches. In general, car use could be reduced between 6% and 55%, while use of the alternative mode (walking, biking and/or public transport) increased between 11% and 150%.[30] These results indicate a shift to action or maintenance stage, some researchers investigated attitude shifts such as the willingness to change. Attitudes towards using alternative modes improved with approximately 20% to 70%.[30] Many of the intervention studies did not clearly differentiate between the five stages, but categorised participants in pre-action and action stage. This approach makes it difficult to assess the effects per stage. Also, interventions included different processes of change; in many cases these processes are not matched to the recommended stage.[30] It highlights the need to develop a standardised approach for travel intervention design. Identifying and assessing which processes are most effective in the context of travel behaviour change should be a priority in the future in order to secure the role of TTM in travel behaviour research.
The TTM has been called "arguably the dominant model of health behaviour change, having received unprecedented research attention, yet it has simultaneously attracted criticism".[14] Depending on the field of application (e.g. smoking cessation, substance abuse, condom use, diabetes treatment, obesity and travel) somewhat different criticisms have been raised.
In a systematic review, published in 2003, of 23 randomized controlled trials, the authors found that "stage based interventions are no more effective than non-stage bas
In a systematic review, published in 2003, of 23 randomized controlled trials, the authors found that "stage based interventions are no more effective than non-stage based interventions or no intervention in changing smoking behaviour.[69] However, it was also mentioned that stage based interventions are often used and implemented inadequately in practice. Thus, criticism is directed towards the use rather the effectiveness of the model itself. Looking at interventions targeting smoking cessation in pregnancy found that stage-matched interventions were more effective than non-matched interventions. One reason for this was the greater intensity of stage-matched interventions.[70] Also, the use of stage-based interventions for smoking cessation in mental illness proved to be effective.[71] Further studies, e.g. a randomized controlled trial published in 2009, found no evidence that a TTM based smoking cessation intervention was more effective than a control intervention not tailored to stage of change. The study claims that those not wanting to change (i.e. precontemplators) tend to be responsive to neither stage nor non-stage based interventions. Since stage-based interventions tend to be more intensive they appear to be most effective at targeting contemplators and above rather than pre-contemplators.[72] A 2010 systematic review of smoking cessation studies under the auspices of the Cochrane Collaboration found that "stage-based self-help interventions (expert systems and/or tailored materials) and individual counselling were neither more nor less effective than their non-stage-based equivalents.[73]
Main criticism is raised regarding the "arbitrary dividing lines" that are drawn between the stages. West claimed that a more coherent and distinguishable definition for the stages is needed.[18] Especially the fact that the stages are bound to a specific time interval is perceived to be misleading. Additionally, the effectiveness of stage-based interventions differs depending on the behavior. A continuous version of the model has been proposed, where each process is first increasingly used, and then decreases in importance, as smokers make progress along some latent dimension.[74] This proposal suggests the use of processes without reference to stages of change.
The model "assumes that individuals typically make coherent and stable plans", when in fact they often do not.[18]
Within research on prevention of pregnancy and sexually transmitted diseases a systematic review from 2003 comes to the conclusion that "no strong conclusions" can be drawn about the effectiveness of interventions based on the transtheoretical model.[75] Again this conclusion is reached due to the inconsistency of use and implementation of the model.[75] This study also confirms that the better stage-matched the intervention the more effect it has to encourage condom use.[75]
Within the health research domain, a 2005 systematic review of 37 randomized controlled trials claims that "there was limited evidence for the effectiveness of stage-based interventions as a basis for behavior change.[76] Studies with which focused on increasing physical activity levels through active commute however showed that stage-matched interventions tended to have slightly more effect than non-stage matched interventions.[60] Since many studies do not use all constructs of the TTM, additional research suggested that the effectiveness of interventions increases the better it is tailored on all core constructs of the TTM in addition to stage of change.[77] In diabetes research the "existing data are insufficient for drawing conclusions on the benefits of the transtheoretical model" as related to dietary interventions. Again, studies with slightly different design, e.g. using different processes, proved to be effective in predicting the stage transition of intention to exercise in relation to treating patients with diabetes.[78]
TTM has generally found a greater popularity regarding research on physical activity, due to the increasing problems associated with unhealthy diets and sedentary living, e.g. obesity, cardiovascular problems.[79] A 2011 Cochrane Systematic Review found that there is little evidence to suggest that using the Transtheoretical Model Stages of Change (TTM SOC) method is effective in helping obese and overweight people lose weight. There were only five studies in the Review, two of which were later dropped due to not being relevant since they did not measure weight. Earlier in a 2009 paper, the TTM was considered to be useful in promoting physical activity. In this study, the algorithms and questionnaires that researchers used to assign people to stages of change lacked standardisation to be compared empirically, or validated.[80][18]
Similar criticism regarding the standardisation as well as consistency in the use of TTM is also raised in a recent review on travel interventions.[30] With regard to travel interventions only stages of change and sometimes decisional balance constructs are included. The processes used to build the intervention are rarely stage-matched and short cuts are taken by classifying participants in a pre-action stage, which summarises the precontemplation, contemplation and preparation stage, and an action/maintenance stage.[30] More generally, TTM has been criticised within various domains due to the limitations in the research designs. For example, many studies supporting the model have been cross-sectional, but longitudinal study data would allow for stronger causal inferences. Another point of criticism is raised in a 2002 review, where the model's stages were characterized as "not mutually exclusive".[81] Furthermore, there was "scant evidence of sequential movement through discrete stages".[81] While research suggests that movement through the stages of change is not always linear, a study conducted in 1996 demonstrated that the probability of forward stage movement is greater than the probability of backward stage movement.[82] Due to the variations in use, implementation and type of research designs, data confirming TTM are ambiguous. More care has to be taken in using a sufficient amount of constructs, trustworthy measures, and longitudinal data.[30]