Behaviour change models: WACE Year 12 Health Studies Unit 3
“Apply behaviour change models, including the Health Belief Model and the stages of change, to explain and influence health behaviour”
Behaviour change models explain why people do or do not adopt healthier behaviour and how to influence them. The Health Belief Model says a person acts when they believe they are susceptible to a serious problem, that the benefits of acting outweigh the barriers, and when a cue triggers action and they feel able to do it. The stages of change model says people move through precontemplation, contemplation, preparation, action, maintenance and sometimes relapse. WACE wants you to apply these models to a scenario, not just list their parts.
What this dot point is asking
WACE expects you to use the models as tools to diagnose where a person is stuck and design a response. A strong answer names the relevant constructs or stage, matches them to the scenario, and proposes a strategy that targets that specific construct or stage. Marks reward correct, applied use rather than a memorised list of parts.
The Health Belief Model
The Health Belief Model explains an individual decision through a set of beliefs. Perceived susceptibility is how likely the person thinks they are to experience the problem. Perceived severity is how serious they judge the consequences to be. Together these create perceived threat. Perceived benefits are the person's view of how much a recommended action would help, and perceived barriers are the costs, effort or inconvenience of acting. The person acts when benefits clearly outweigh barriers. Cues to action are triggers such as a symptom, a friend's diagnosis or a campaign, and self-efficacy is the person's confidence that they can actually perform the behaviour.
The model is useful because it tells you exactly what to change. If a young person does not use sunscreen because they feel skin cancer will not happen to them, the barrier is low perceived susceptibility, so the strategy should raise their sense of personal risk. If they accept the risk but find sunscreen greasy and expensive, the barrier is perceived barriers, so the strategy should reduce cost and inconvenience.
Self-efficacy is a person's belief in their own ability to successfully carry out a behaviour. It is a key construct because even someone who accepts the risk and the benefits will not act if they do not believe they can. Building self-efficacy through skills, small achievable steps and encouragement is often the difference between intention and action.
The stages of change
The stages of change (transtheoretical) model describes behaviour change as a process over time rather than a single decision. In precontemplation the person is not thinking about change and may not see a problem. In contemplation they are aware of the problem and weighing change but feel ambivalent. In preparation they intend to act soon and may take small steps. In action they have changed the behaviour recently. In maintenance they have sustained the change and work to prevent slipping back. Relapse is a return to the old behaviour, treated as a normal part of the cycle rather than a failure.
The value of this model is that it matches the strategy to the stage. A person in precontemplation needs information and a reason to care, not a quit-smoking timetable. A person in action needs support, coping skills and relapse prevention, not basic awareness. Pushing an action-stage strategy onto a precontemplation-stage person usually fails, so identifying the stage first is essential.
The whole point of these models is targeting. A strategy that fits one stage or belief is wrong for another, so the same advice can succeed or fail depending on where the person is. Diagnose the barrier construct in the Health Belief Model, or the stage in the stages of change, before choosing the response, because the matched strategy is what moves the person forward.
Using the models together
The two models answer different questions. The Health Belief Model explains the weighing of beliefs behind a single decision, while the stages of change explain the journey over time. Used together, you can diagnose both why a person is hesitating (which belief is the barrier) and where they are in the process (which stage), then design a response that fits both.
How this maps to the exam
Expect a stimulus describing a person who has or has not changed a behaviour. Identify the relevant constructs of the Health Belief Model or the stage of change, explain what is driving the behaviour, and propose a strategy that targets that exact construct or stage. Use the details in the scenario rather than generic advice.
A common stem gives a person who knows a risk but has not acted, then asks you to apply the Health Belief Model. Work through it in this order.
Identify the construct that is blocking action
Jordan, 17, never wears sunscreen at the beach even though he knows about skin cancer. Start by naming the blocking construct: his perceived susceptibility is low ("a tan is healthy, melanoma happens to older people"), and perceived barriers are high (sunscreen feels greasy and he forgets to bring it). His knowledge is a cue, but it is outweighed by these beliefs.
Explain the prediction the model makes
The Health Belief Model predicts Jordan will not act while benefits do not clearly outweigh barriers and threat feels low. He does not feel personally at risk, so the perceived benefit of sunscreen seems small relative to the inconvenience.
Match a strategy to that construct
Target perceived susceptibility with personalised information (a UV camera image showing existing sun damage on his own skin) so the risk feels real and immediate. Then target the barrier by making sunscreen convenient and normal among his peers (free spray stations, friends using it together), which also builds self-efficacy.
Close with the expected change
With raised susceptibility and lowered barriers, the model predicts benefits now outweigh barriers, so Jordan is more likely to apply sunscreen. Naming the construct, the prediction and the matched strategy is what earns full marks.
Students often write out every construct of the Health Belief Model or every stage of change without linking them to the person in the stimulus. The marks come from identifying which construct or stage applies and matching a strategy to it. Name the specific barrier or stage, then explain the targeted response.
Exam-style questions
Questions in the style of SCSA exam questions on this dot point, each with a worked answer. They are written by ExamExplained unless tagged "Past paper"; the year shows the paper a question is modelled on.
WACE 2022-style8 marksA 16 year old continues to vape despite knowing the health risks. Using the Health Belief Model, explain why this person may not have changed their behaviour and recommend two strategies to support change.Show worked answer →
An 8 mark response needs the relevant constructs named, applied to the person, and two targeted strategies.
- Diagnose the barriers
- Low perceived susceptibility: at 16 the person feels harm is distant and unlikely to affect them. Low perceived severity: they may see vaping as far safer than smoking. High perceived barriers: vaping relieves stress and is part of their social group, so quitting carries social and emotional costs. Knowing the risks (a cue) is not enough while these beliefs block action, and low self-efficacy means they doubt they could stop.
- Strategy 1 (target susceptibility/severity)
- Use personalised, peer-relevant information (for example testimony from a young person with nicotine addiction or lung damage) to raise perceived personal risk so the threat feels real and immediate.
- Strategy 2 (target barriers/self-efficacy)
- Teach refusal skills and provide quit support so the person can manage stress and social pressure another way, lowering the barriers and building confidence that they can succeed.
Markers reward correct construct names, application to this person, and strategies matched to the diagnosed barrier rather than generic advice.
WACE 2023-style4 marksDescribe the stages of change (transtheoretical) model and explain why support must be matched to a person's stage.Show worked answer →
A 4 mark response needs the stages in order and the reason matching matters.
Stages. Precontemplation (not considering change), contemplation (weighing it up), preparation (planning and small steps), action (actively changing), maintenance (sustaining the change), with relapse possible.
Why match. Each stage needs different help: a precontemplation-stage person needs a reason to care, not a detailed plan, while an action-stage person needs coping skills and relapse prevention. A mismatched strategy usually fails, so identifying the stage first determines the right response.
Markers reward the stages in order and a clear explanation that the strategy must fit the stage.