The HBM contains several primary concepts that predict why people will take action to prevent, to screen for, or to control illness conditions; these include susceptibility, seriousness, benefits and barriers to a behavior, cues to action, and most recently,
self-efficacy. Initially, Hochbaum (1958) studied perceptions about whether indi- viduals believed they were susceptible to tuberculosis and their beliefs about the per- sonal benefits of early detection (Hochbaum, 1958). Among individuals who exhibited beliefs both in their own susceptibility to tuberculosis and about the overall benefits from early detection, 82 percent had at least one voluntary chest X-ray. Of the group exhibiting neither of these beliefs, only 21 percent had obtained voluntary X-rays during the criterion period.
If individuals regard themselves as susceptible to a condition, believe that con- dition would have potentially serious consequences, believe that a course of action available to them would be beneficial in reducing either their susceptibility to or sever- ity of the condition, and believe the anticipated benefits of taking action outweigh the barriers to (or costs of) action, they are likely to take action that they believe will reduce their risks.
In the case of medically established illness (rather than mere risk reduction), the dimension has been reformulated to include acceptance of the diagnosis, personal estimates of susceptibility to consequences of the illness, and susceptibility to illness in general. Definitions of the HBM constructs follow. Table 3.1 summarizes the con- structs, definitions, and application examples, and Figure 3.1 illustrates the rela- tionships among constructs.
Constructs
Perceived Susceptibility. Perceived susceptibility refers to beliefs about the likelihood of getting a disease or condition. For instance, a woman must believe there is a possi- bility of getting breast cancer before she will be interested in obtaining a mammogram.
Perceived Severity. Feelings about the seriousness of contracting an illness or of leaving it untreated include evaluations of both medical and clinical consequences (for example, death, disability, and pain) and possible social consequences (such as effects of the conditions on work, family life, and social relations). The combina- tion of susceptibility and severity has been labeled as perceived threat.
Perceived Benefits. Even if a person perceives personal susceptibility to a serious health condition (perceived threat), whether this perception leads to behavior change will be influenced by the person’s beliefs regarding perceived benefits of the various available actions for reducing the disease threat. Other non-health-related percep- tions, such as the financial savings related to quitting smoking or pleasing a family member by having a mammogram, may also influence behavioral decisions. Thus, individuals exhibiting optimal beliefs in susceptibility and severity are not expected to accept any recommended health action unless they also perceive the action as po- tentially beneficial by reducing the threat.
Perceived Barriers. The potential negative aspects of a particular health action—per- ceived barriers—may act as impediments to undertaking recommended behaviors. A kind of nonconscious, cost-benefit analysis occurs wherein individuals weigh the action’s expected benefits with perceived barriers—“It could help me, but it may be
TABLE 3.1.
Key Concepts and Definitions of the Health Belief Model.Concept Definition Application
Perceived susceptibility
Perceived severity
Perceived benefits
Perceived barriers
Cues to action
Self-efficacy
Belief about the chances of experiencing a risk or getting a condition or disease
Belief about how serious a condition and its sequelae are Belief in efficacy of the advised action to reduce risk or seriousness of impact Belief about the tangible and psychological costs of the advised action
Strategies to activate
“readiness”
Confidence in one’s ability to take action
Define population(s) at risk, risk levels
Personalize risk based on a person’s characteristics or behavior
Make perceived susceptibility more consistent with individual’s actual risk Specify consequences of risks and conditions
Define action to take: how, where, when; clarify the positive effects to be expected Identify and reduce perceived barriers through reassurance, correction of misinformation, incentives, assistance Provide how-to information, promote awareness, use appropriate reminder systems Provide training and
guidance in performing recommended action Use progressive goal setting Give verbal reinforcement Demonstrate desired behaviors
Reduce anxiety
expensive, have negative side effects, be unpleasant, inconvenient, or time-consuming.”
Thus, “combined levels of susceptibility and severity provide the energy or force to act and the perception of benefits (minus barriers) provide a preferred path of action”
(Rosenstock, 1974).
Cues to Action. Various early formulations of the HBM included the concept of cues that can trigger actions. Hochbaum (1958), for example, thought that readiness to take action (perceived susceptibility and perceived benefits) could only be potenti- ated by other factors, particularly by cues to instigate action, such as bodily events, or by environmental events, such as media publicity. He did not, however, study the role of cues empirically. Nor have cues to action been systematically studied. Indeed, although the concept of cues as triggering mechanisms is appealing, cues to action are difficult to study in explanatory surveys; a cue can be as fleeting as a sneeze or the barely conscious perception of a poster.
Self-Efficacy. Self-efficacy is defined as “the conviction that one can successfully ex- ecute the behavior required to produce the outcomes” (Bandura, 1997). Bandura dis- tinguished self-efficacy expectations from outcome expectations, defined as a person’s estimate that a given behavior will lead to certain outcomes. Outcome expectations are similar to but distinct from the HBM concept of perceived benefits. In 1988, Rosen- stock, Strecher, and Becker suggested that self-efficacy be added to the HBM as a separate construct, while including original concepts of susceptibility, severity, ben- efits, and barriers.
Self-efficacy was never explicitly incorporated into early formulations of the HBM. The original model was developed in the context of circumscribed preventive health actions (accepting a screening test or an immunization) that were not perceived to involve complex behaviors.
FIGURE 3.1.
Health Belief Model Components and Linkages.Modifying Factors Individual Beliefs Action
Perceived susceptibility to and severity
of disease Age
Gender Ethnicity Personality Socioeconomics
Knowledge
Perceived benefits
Perceived threat
Individual behaviors Perceived
barriers Perceived self-efficacy
Cues to action
As discussed more thoroughly in Chapter Eight (on Social Cognitive Theory), a body of literature supports the importance of self-efficacy in initiation and mainte- nance of behavioral change (Bandura, 1997). For behavior change to succeed, people must (as the original HBM theorizes) feel threatened by their current behavioral pat- terns (perceived susceptibility and severity) and believe that change of a specific kind will result in a valued outcome at an acceptable cost (perceived benefit). They also must feel themselves competent (self-efficacious) to overcome perceived barriers to take action.
Other Variables. Diverse demographic, sociopsychological, and structural variables may influence perceptions and, thus, indirectly influence health-related behavior. For example, sociodemographic factors, particularly educational attainment, are believed to have an indirect effect on behavior by influencing the perception of susceptibil- ity, severity, benefits, and barriers.
Relationships Among Health Belief Model Constructs
The HBM components are depicted in Figure 3.1. Arrows indicate relationships be- tween constructs. Modifying factors include knowledge and sociodemographic fac- tors that may influence health perceptions. Health beliefs include the major constructs of the HBM: susceptibility, severity, benefits, barriers, and self-efficacy. Modifying factors affect these perceptions, as do cues to action. The combination of beliefs leads to behavior. Within the “health belief” box, perceived susceptibility and severity are combined to identify threat.
Although the HBM identifies constructs that lead to outcome behaviors, relation- ships between and among these constructs are not defined. This ambiguity has led to variation in HBM applications. For example, whereas many studies have attempted to establish each of the major dimensions as independent, others have tried multi- plicative approaches. Analytical approaches to identifying these relationships are needed to further the utility of the HBM in predicting behavior.