Paying people to change their behaviour can work, at least in the short term. However, there are many unanswered questions about this approach, conclude researchers in a paper published on bmj today.

Personal financial incentives are increasingly being used to motivate patients and general populations to change their behaviour, most often as part of schemes aimed at reducing rates of obesity, smoking, and other addictive behaviours, write Theresa Marteau, Professor of Health Psychology at Kings College London, and colleagues.

For example, a smoking cessation scheme in Essex offers pregnant women £20 food vouchers for one week cessation; £40 after four weeks; and another £40 at one year. And in Tanzania, men and women aged 15-30 receive $45 for regular negative laboratory tests for sexually transmitted diseases.

They reviewed evidence on the effectiveness of financial incentives in achieving health related behaviour change and examined the basis for concerns about their use.

In theory, financial incentives work by providing an immediate reward for behaviours that usually provide health gains in the longer term. They also capitalise on the tendency for many of us to pursue smaller immediate rewards instead of rewards that are distant but more highly valued.

Evidence shows that schemes targeting habitual behaviours such as smoking or physical inactivity in high income countries may be more effective if they provide incentives for initial as well as sustained behaviour change, explain the authors. In contrast, for schemes aimed at initiating relatively simple behaviours in low income populations, such as clinic attendance and participation in vaccination programmes, small incentives delivered immediately seem most effective.

But financial incentives can also have unintended effects on motivation, informed choices, and the doctor-patient relationship, warn the authors. The use of incentives also raise moral questions about whether incentives reward and even encourage adverse behaviours, and whether the effect of incentives differs among socioeconomic groups. More studies are needed to address these concerns, they write.

Opinion on the use of incentives varies, but the authors suggest that offering a reward can help people to align their actions more closely with their true preferences. For example, most people would prefer to eat more healthily and to be more physically active than they actually are. In this way, incentives operate to enhance rather than to restrict autonomy, they say.

They believe that offering personal financial incentives is one of several means by which behaviour may be changed and should be seen as part of a broad approach. Even when effective, the use of financial incentives will depend on its acceptability to general populations, healthcare professionals, and policy makers alike.

Ultimately, if personal financial incentives prove to be effective and acceptable in only a few contexts, they may still offer an important means by which to improve population health, they conclude.

"Analysis: Using financial incentives to achieve healthy behaviour."
BMJ online