A Definition and Description of the Four Theories
The theory of reasoned action, health belief model, theory of planned behavior, and the trans-theoretical change model are the most commonly used theories in public health (Glanz & Bishop, 2010). The theory of reasoned action predicts human behavior by analyzing human attitudes. Developed by Ajzen and Fishbein, the theory of reasoned action demonstrates that people’s health behaviors stem from their attitudes about the health issue (Glanz & Bishop, 2010). Similarly, it argues that people’s subjective norms affect their health behaviors (Glanz, Rimer, & Viswanath, 2008). Broadly, this theory emerged from frustrations about past studies that found a weak relationship between people’s attitudes and behavioral responses (Glanz & Bishop, 2010). Unlike the theory of reasoned action, which based its principles on human attitudes, the health belief model developed its principles from people’s psychological conditions (Glanz & Bishop, 2010). It argued that people’s willingness to embrace public health interventions depended on their perceived understanding of their benefits, their associated health problems, the cost of adoption, and self-efficacy issues (Glanz et al., 2008). Developed by social psychologists, the health belief model demonstrates that people’s willingness to engage in a health-promoting behavior depends on the presence of a stimulus (Glanz & Bishop, 2010). The theory of planned behavior adopts a broader understanding of people’s behaviors by including perceived behavioral controls as a contributor to people’s willingness to engage in health-promoting behaviors (Fishbein, 2008). In this regard, unlike the theory of reasoned action, which only focuses on human attitudes to predict behavior, it proposes that people’s attitudes, subjective norms, and behavioral control affect their propensity to adopt health-promoting behavior (Fishbein, 2008). Lastly, the trans-theoretical model posits that most people undergo six stages of behavior change to embrace health-promoting behavior (these stages include pre-contemplation, contemplation, preparation, action, maintenance and termination) (Glanz & Bishop, 2010). Unlike other theories, which focus on specific aspects of change, the trans-theoretical model uses all aspects of change to explain people’s behavioral responses to health changes.
How each of the Four Theories apply to Public Health
Theory of Reasoned Action
Public health researchers have used the theory of reasoned action to create interventions that resonate with different demographics (Glanz & Bishop, 2010). For example, researchers have used it to develop women’s health programs and core interventions that relate to the same (Fishbein, 2008).
The Health Belief Model
The health belief model is arguably the most commonly used theory in public health. For example, public health practitioners have used it in sex education campaigns for preventing new HIV infections (Fishbein, 2008). Others have used it to promote the uptake of healthy diets and encourage people to adopt weight control interventions (Glanz & Bishop, 2010).
Theory of Planned Behavior
The theory of planned behavior is useful in public health because it helps to expose the critical behavioral, normative, and control beliefs that affect the success, or failure, of health interventions (Fishbein, 2008). In this regard, experts have used it in health promotion programs. For example, public health administrators have used it in applied nutrition intervention programs to encourage parents to give children nutritious foods when in school (Fishbein, 2008).
The Trans-theoretical Stages of Change
Public health practitioners have used the trans-theoretical stages of change model to promote a better quality of life among different communities (Glanz & Bishop, 2010). Particularly, since its introduction, researchers have used it to design health promotion programs for preventing young people from smoking (Glanz et al., 2008). In this regard, health researchers have used it to explain why some people could quit smoking without much help and why others need rehabilitation to do so. Besides smoking cessation, people have also used the theory to promote healthy diets, treatment adherence, and increase cancer screening among young women (Glanz et al., 2008).
Strengths of Each of the Four Theories
Theory of Reasoned Action
The greatest strength of the theory of reasoned action is its relative simplicity in identifying when and how public health practitioners should formulate and target health interventions. Furthermore, it predicts people’s behaviors better than other theories do (Glanz et al., 2008).
The Health Belief Model
Unlike other health models and theories, the health belief model could explain the success, or failure, of a public health intervention. For example, it successfully explained why past tuberculosis screening programs failed to meet their goals (Glanz et al., 2008).
Theory of Planned Behavior
The greatest strength of the theory of planned behavior is its predictive ability. In this regard, it could effectively predict the success, or failure, of public health interventions. This ability presents it as a complementary part to the health belief model, which explains the successes, or failures, of health interventions (Glanz et al., 2008).
The Trans-theoretical Stages of Change
The main strength of the trans-theoretical theory is its ability to link different theoretical concepts in one theory. It uses a temporal dimension to explain human behavior (Fishbein, 2008). This way, it gives a holistic approach to behavior change.
Limitations of Each of the Four Theories
Theory of Reasoned Action
Since the theory of reasoned action relies on people’s intentions to predict human behavior, it fails to consider external factors that affect people’s intentions, such as available choices, ambiguity between intentions and expectations, and the ambiguity between a goal intention and a behavior intention (Fishbein, 2008).
The Health Belief Model
The success of the health belief model depends on having a correct understanding of people’s attitudes and beliefs about a health intervention (Fishbein, 2008). The health belief model does not adopt a holistic understanding of all the factors that could affect human behaviors. This limitation emerges from the proven effects of external environmental factors (outside an individual’s scope) that may influence health behavior.
Theory of Planned Behavior
This paper has already shown that the theory of planned behavior helps us to know the critical behavioral, normative, and control beliefs that affect the success, or failure, of health interventions. Although this contribution is critical to the design of public health interventions, the theory does not explain how to change these beliefs to realize positive health outcomes. In this regard, public health workers have trouble designing communications, and other types of health interventions, that would create positive health outcomes (Glanz et al., 2008).
The Trans-theoretical Stages of Change
The greatest weakness of the trans-theoretical model of health behavior is its ignorance of change contexts. For example, it fails to acknowledge the effects of socioeconomic statuses and income disparities in predicting behavioral changes.
Which Theory would best apply to my Public Health Campaign? (Ebola in Sierra Leone)
The theory of reasoned action is the best model to use in predicting the success, or failure, of public health interventions for reducing Ebola infections in Sierra Leone. Most of the health challenges reported by health care service providers in West Africa emanated from attitudinal inhibitions (World Health Organization, 2015). For example, conspiracy theories about the origin of the disease and its treatment methods made some local communities resistant to western medicine (World Health Organization, 2015). Some of these attitudinal factors have also created a wrong perception that the infection would disappear because it is a “bad omen” (World Health Organization, 2015). Since the theory of reasoned action focuses on attitudinal factors to explain people’s health behaviors, it is the best theory to use in my public health intervention.
References
Fishbein, M. (2008). A Reasoned Action Approach to Health Promotion. Med Decision Making 28(6), 834-844.
Glanz, K., & Bishop, D. B. (2010). The role of behavioral science theory in development and implementation of public health interventions. Annual Review of Public Health, 31, 399–418.
Glanz, K., Rimer, B. K., &Viswanath, K. (Eds.). (2008). Health behavior and health education: Theory, research, and practice (4th ed.). San Francisco, CA: John Wiley & Sons.
World Health Organization (WHO). (2015). Sierra Leone: a traditional healer and a funeral. Web.