Montreal for n Limitations of the TTM n Prochaska and di Clemente made suggestions for a time-frame within which they distinguish contemplaters from preparers i.e. thinking of changing but not in the next six months versus thinking of changing within the next three months, but there is little empirical evidence that these are qualitatively different or differ in terms of the attitudes or intentions of stage members e.g. Godin et al. Kraft et al n Past behaviour has subsequently been found to be a powerful predictor of future behaviour change efforts. This has questioned the usefulness of stages, where readiness or intentions to change are assumed to be key Table Stages in the transtheoretical model and the precaution adoption process model Stage Transtheoretical model Precaution adoption process model pre-contemplation unaware of issue contemplation unengaged preparation considering whether to act action deciding not to act and exit the model maintenance deciding to act and proceed to next stage action maintenance Sutton For example, Godin et al. Montreal 2016.