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. The model is composed of constructs such as: stages of change, processes of change, levels of change, self-efficacy, and decisional balance. The transtheoretical model is also known by the abbreviation "TTM" and sometimes by the term "stages of change", 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. Several self-help books—Changing for Good (1994), Changeology (2012), and Changing to Thrive (2016)—and articles in the news media 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". History and core constructs James O. Prochaska of the University of Rhode Island, and Carlo Di Clemente and colleagues developed the transtheoretical model beginning in 1977. It is based on analysis and use of different theories of psychotherapy, hence the name "transtheoretical". Prochaska and colleagues refined the model on the basis of research that they published in peer-reviewed journals and books. Stages of change This construct refers to the temporal dimension of behavioural change. In the transtheoretical model, change is a "process involving progress through a series of stages": Precontemplation ("not ready") – "People are not intending to take action in the foreseeable future, and can be unaware that their behaviour is problematic" Contemplation ("getting ready") – "People are beginning to recognize that their behaviour is problematic, and start to look at the pros and cons of their continued actions" Preparation ("ready") – "People are intending to take action in the immediate future, and may begin taking small steps toward behaviour change" Action – "People have made specific overt modifications in modifying their problem behaviour or in acquiring new healthy behaviours" Maintenance – "People have been able to sustain action for at least six months and are working to prevent relapse" Termination – "Individuals have zero temptation and they are sure they will not return to their old unhealthy habit as a way of coping" In addition, the researchers conceptualized "Relapse" (recycling) which is not a stage in itself but rather the "return from Action or Maintenance to an earlier stage". The quantitative