This model suggests that behavioral change is a process that involves various changes in an individual (Prochaska and Velicer, 1997). Such pattern of this model has led to both acknowledgment and debates surrounding this model. The model has been applied to measure various behavioral patterns (Fern, 2008). On the other hand, the model has been criticized for not having enough conceptual clarity (West, 2005). The effectiveness of many health promotion programs were measured by this model. Yet, West (2005) argued that the differences between the stages in this model are too shallow and overlapping to distinguish.The fundamental belief of Stages of Change model is, it does not happen overnight and different individual progress in different rates. Again, the individuals has the decision making power to judge which stage they belong to (Kern, 2008). It is connected with individual willpower and agency practice. Thus, the ideal application of this model can result in modifying a problem behavior and adopting a positive behavior (Velicer, Prochaska, Fava, Norman & Redding, 1998). However, like many theories, the application differs from individual to individuals. Not all individuals remain sorted and organized while changing an old behavior (West, 2005). Some people might skip one or two stages to advance while others may abandon after completing first or second stage.
There are some other criticisms of this model as well. One of the major criticisms of this model is actually how many stages are there in this model? Prochaska and Velicer (1997) have mentioned that there are six stages of change. While other thinkers have mentioned that there five stages of change. There are different opinions about the final stage as well. Kern (2008) denotes the final stage as relapse where an individual might revert to his/her old behavior. Kern (2008) even went on to add another stage which is called transcendence; where the old habit would look like abnormal to the individual who once were addicted to it. On the hand, Prochaska and Velicer (1997) have coined the final stage as termination, where an individual have adopted the new behavior unconditionally.
There are both criticisms and acceptability of stages of change model. Not all cases might fit into this model yet it can be applied to many cases of behavior change. So, in my opinion, accepting or rejecting a model cannot be a simple choice.