Theories Used in Public Health

v  Health Belief Model (HBM): HBM is a psychological framework used in public health to explain and predict individual health behaviors by focusing on personal beliefs and perceptions. It suggests that people are more likely to take preventive actions if they believe they are at risk, that the condition is serious, that the action will reduce their risk, and that the benefits outweigh the barriers. Additionally, cues to action (such as media messages or symptoms) and self-efficacy (confidence in one's ability to take action) play crucial roles in this process. The HBM is widely applied in areas such as vaccination campaigns, disease screening, and the management of chronic illnesses. Example: COVID-19 Vaccination Campaigns.

v  Theory of Planned Behavior (TPB): TPB is a social psychological theory that explains how individual behavior is guided by intentions, which are influenced by three key factors: attitude toward the behavior, subjective norms, and perceived behavioral control. The stronger these factors are, the more likely a person is to form the intention to engage in the behavior, which in turn predicts actual behavior. TPB is widely used in public health to understand and influence behaviors such as smoking cessation, physical activity, safe sex practices, and healthy eating. Example: Smoking Cessation Programs

v  Transtheoretical Model (Stages of Change): TTM, also called the Stages of Change Model, shows that behavior change happens in steps over time. It has six stages: Precontemplation, Contemplation, Preparation, Action, Maintenance, and sometimes Decline. This model helps create support based on a person's readiness to change. It is often used in public health for activities such as quitting addiction, losing weight, and exercising more. The model suggests that changing behavior is not a linear process, but rather a cyclical one. For example, it is used in weight loss programs.

v  Social Cognitive Theory (SCT): SCT explains health behavior as a result of the dynamic interaction between personal factors, environmental influences, and behavior itself, known as reciprocal determinism. Key concepts include observational learning, self-efficacy, outcome expectations, and reinforcements. SCT emphasizes that people can learn and change behaviors through modeling, feedback, and self-regulation. It is widely used in designing public health programs such as HIV/AIDS education, physical activity promotion, and smoking prevention. Example: HIV/AIDS Awareness Campaigns.

v  Social Support Theory: Social Support Theory highlights the role of social relationships in influencing health behaviors and outcomes. It emphasizes that support from others, such as family, friends, or community members, can have a profoundly positive impact on both physical and mental health. There are four main types of support: emotional, instrumental, informational, and appraisal. This theory is commonly applied in public health areas, such as maternal health, chronic disease management, mental health support, and recovery from illness, where strong social networks enhance coping, treatment adherence, and overall well-being, as seen in Breastfeeding Promotion Programs.

v  Social Ecological Model (SEM): SEM is a framework that explains how multiple levels of influence shape individual health behaviors. It recognizes that behavior is affected not only by personal factors but also by relationships, community structures, institutions, and public policy. The model includes five levels: individual, interpersonal, organizational, community, and policy. SEM is widely used in public health to design multi-level interventions — for example, in obesity prevention, tobacco control, and violence reduction — by addressing factors across all layers of influence, such as obesity prevention programs.

v  Diffusion of Innovations Theory: Diffusion of innovations theory explains how new ideas, practices, or technologies spread within a society or social system over time. It identifies groups based on their willingness to adopt innovations: innovators, early adopters, early majority, late majority, and laggards. Adoption is influenced by factors like the innovation's relative advantage, compatibility, complexity, trialability, and observability. This theory is widely applied in public health to promote the adoption of new health behaviors, treatments, or technologies, such as the use of oral rehydration therapy, vaccination programs, or digital health tools. Example: Adoption of Oral Rehydration Therapy in Rural Areas.

v  PRECEDE–PROCEED Model: This model is a comprehensive planning framework used to design, implement, and evaluate public health programs. PRECEDE involves assessing social, epidemiological, behavioral, and environmental factors to identify needs and priorities. PROCEED focuses on implementing interventions and evaluating their effectiveness. This model enables public health practitioners to create tailored, evidence-based interventions by systematically analyzing the factors that influence health behaviors and outcomes, for example, the Teen Pregnancy Prevention Program.

v  COM-B Model: The COM-B Model explains behavior as the result of the interaction between three components: Capability, Opportunity, and Motivation. For behavior change to occur, all three must be present. This model is widely used in designing effective public health interventions by identifying what needs to change to enable desired behaviors, such as improving hand hygiene or increasing physical activity—for example: Hand Hygiene in Hospitals.