In order to succeed in the essential Public Health functions of assessment and education, Public Health professionals use a variety of health and behavior theories, some of which have been previously discussed in this book. These theories may be oriented toward behavioral explanation or behavioral change, depending on the intended outcome. Different theories may progress in similar stages (such as the Transtheoretical Model Stages of Change and the Precaution Adoption Access Model), while others offer insight into concepts as specific as the embracing of new health ideas (Diffusion of Innovation Theory). However, despite their similarities and differences, any one health concern can be applied to nearly all of them. For instance, the Social-Ecological model may explain the factors that influence rates of childhood obesity in a particular demographic, while the Transtheoretical Model Stages of Change will provide insight on an individual’s thought process in regard to losing weight or living a healthier lifestyle.

Traditional health theories, such as the Theory of Planned Behavior or the Health Belief Model, focus on the variables influencing health behavior, in addition to predicting the eventual health behavior itself. Stage theories such as the Transtheoretical Model or the Precaution Adoption Process Model differ from traditional theories in that they emphasize health behaviors are not merely a single lifestyle choice, but rather a series of choices over time.