Dani Bancroft

Dani Bancroft

Theory for the real world: behaviour change and public health

16 March 2022

people walking along the street wearing face masks

The theory underpinning behaviour change can be applied to a range of real-world problems in public health. But why should we direct our attention to theory to find solutions?

There are ‘blueprints’ for behaviour change that are applicable to multiple public health-related disciplines. From understanding how healthy eating campaigns are received by the public, to combatting emerging infectious diseases, all have roots grounded in theory.

Still, the theory behind more complex behaviours is sometimes overlooked in practical conversations around public health. In this blog I have outlined a few scenarios where theory can be applied to tackle real-world public health challenges.


Challenge 1: A new generation of smokers

Despite almost 70 years of rigorous evidence on the harms of tobacco, changes in regulation, packaging and price of cigarettes, and quit-smoking campaigns, we still have a new generation of smokers. One analysis estimated that every day, 67 children start smoking in London – more than two classrooms’ full.

To help us understand why, we can turn to theoretical frameworks for behaviour change, such as the Theory of Reasoned Action. These can predict the success of an intervention to discourage smoking, including the precise component which may be preventing it from achieving impact. For example, without adequate perceived threat or susceptibility to getting a disease (such as lung cancer or COVID-19), we are rarely motivated to change our behaviour. Interventions can therefore be designed to target each stage of the decision-making process to start and continue to engage in smoking, from how tobacco products are advertised to targeted awareness campaigns on the health risks.

Despite almost 70 years of rigorous evidence on the harms of tobacco, we still have a new generation of smokers.


Challenge 2: Emerging epidemics

Like dengue and yellow fever, Zika virus is primarily spread by the Aedes aegypti mosquito. In 2015, a sharp rise in the number of babies born with microcephaly was linked to the emergence of Zika virus in Brazil. In response, the World Health Organization promptly declared the epidemic a Public Health Emergency of International Concern.

Guidance was issued on how to minimise the risk of contracting the virus, such as wearing long-sleeved clothing and mosquito repellent. Around the home, it was recommended that standing water was treated with larvicides or regularly removed. Pregnant women were advised to avoid travel and stay indoors at times when mosquitos are most active. It was also recommended that non-pregnant women delay pregnancy and use contraceptives during the epidemic. However, despite a series of public health campaigns, Zika rapidly spread to over 87 countries, leading to a generation of children with a series of uniquely complex and devastating disabilities.

One way to understand the perspectives of Brazilian communities affected by Zika virus is through the Health Belief Model, a framework which maps the decision-making process that a new behaviour may entail. This is because each of these behaviours can be strongly informed by a personal assessment of their convenience and cost, as well as how the behaviour may be perceived by loved ones and the wider community.

In a study that I co-authored for the London School of Hygiene & Tropical Medicine, we found that communities affected by the Zika virus epidemic felt that many of these preventive measures were not sustainable in the long term. Additionally, there was a sense that the burden of controlling the epidemic lay too much on them as individuals – especially women. For these reasons, the worldwide epidemic-preparedness community has predicted we have a high risk of Zika virus returning – in addition to outbreaks of similar neglected tropical diseases.

person spraying mosquito repellent on their hand and arm

Communities affected by the Zika virus epidemic felt that many of the prevention measures were not sustainable in the long term.


Challenge 3: Increasing participation in cancer screening programmes

There is strong evidence that lung cancer screening programmes can save lives by detecting the cancer earlier. To be successful, a national screening programme must draw in people at the highest risk of lung cancer. The challenge is to engage them.

Behaviour change frameworks can help us to understand why people at greater risk of lung cancer are sometimes less likely to access free screening appointments. Some experts have used the Capability, Opportunity, Motivation and Behaviour (COM-B) model to break down the underlying conditions that need to be in place for behaviour change. For example, an individual might not consider engaging in a prevention service like screening if they don’t have enough time or a means of transport to get there.

The model demonstrates that even when interventions are put in place to improve access to the physical and financial resources needed for screening, if the psychological and social needs are also not met, uptake may remain low. An example is stigma around lung cancer and smoking, which may cause some people to feel ashamed about their invitation to a screening programme. In this case, some interventions that have been explored include personalised invitations from their doctor, text or postal appointment reminders, and health campaigns to reframe and normalise screening as free ‘servicing’ for their lungs.

Applying the right theoretical framework enables public health professionals to answer questions such as: where can we develop an intervention to lead to population-level behaviour change? What works and what doesn’t? Can the evidence for each component be mapped and measured? And which area should be a priority for government investment?


The opinions expressed in this blog are those of the author and do not necessarily represent the views of The Health Policy Partnership.