The health action process approach (HAPA) is a psychological theory of health behavior change, developed by Ralf Schwarzer, Professor of Psychology at the Free University of Berlin, Germany. The health action process approach (HAPA) is a psychological theory of health behavior change, developed by Ralf Schwarzer, Professor of Psychology at the Free University of Berlin, Germany. Health behavior change refers to a replacement of health-compromising behaviors (such as sedentary behavior) by health-enhancing behaviors (such as physical exercise). To describe, predict, and explain such processes, theories or models are being developed. Health behavioural change theories are designed to examine a set of psychological constructs that jointly aim at explaining what motivates people to change and how they take preventive action. HAPA is an open framework of various motivational and volitional constructs that are assumed to explain and predict individual changes in health behaviors such as quitting smoking or drinking, and improving physical activity levels, dental hygiene, seat belt use, breast self-examination, dietary behaviors, and avoiding drunk driving. HAPA suggests that the adoption, initiation, and maintenance of health behaviors should be conceived of as a structured process including a motivation phase and a volition phase. The former describes the intention formation while the latter refers to planning, and action (initiative, maintenance, recovery). The model emphasizes the particular role of perceived self-efficacy at different stages of health behavior change. Models that describe health behavior change can be distinguished in terms of the assumption whether they are continuum-based or stage-based. A continuum (mediator) model claims that change is a continuous process that leads from lack of motivation via action readiness either to successful change or final disengagement. Research on such mediator models are reflected by path diagrams that include distal and proximal predictors of the target behavior. On the other hand, the stage approach assumes that change is non-linear and consists of several qualitative steps that reflect different mindsets of people. A two-layer framework that can be applied either as a continuum or as a stage model is HAPA. It includes self-efficacy, outcome expectancies, and risk perception as distal predictors, intention as a middle-level mediator, and volitional factors (such as action planning) as the most proximal predictors of behavior. See Self-efficacy. Good intentions are more likely to be translated into action when people plan when, where, and how to perform the desired behavior. Intentions foster planning, which in turn facilitates behavior change. Planning was found to mediate the intention-behavior relation. A distinction has been made between action planning and coping planning. Coping planning takes place when people imagine scenarios that hinder them to perform their intended behavior, and they develop one or more plans to cope with such a challenging situation.