NIHR research has explored the use of incentives in a range of settings, and with different populations. The results have varied, suggesting that incentives are context-dependent, and need to be planned carefully according to the needs and preferences of different groups.
Systematic reviews – which provide an overview of all existing evidence – suggest that financial incentives are generally more effective than usual care or no intervention. These reviews looked at effectiveness across a range of behaviours, including smoking cessation, weight loss and screening attendance. The effects lasted between three and six months for smoking cessation, but for other behaviours did not last long after the incentive stopped. There was not enough evidence to indicate which types of incentive (cash, vouchers, lottery entry or others) were most effective, and a lack of evidence on cost-effectiveness.
Reviews of evidence have suggested that incentives could be an effective way to encourage people to attend screening appointments or check-ups. That may be the case for some population groups or appointment types, but an NIHR trial found that offering small financial incentives – such as £10 in cash, or the opportunity to win £1,000 in a lottery – did not improve attendance at eye screening for people with diabetes. The study recruited people who had not attended their eye screening appointment in the last two years. Some received a standard invitation; others the £10 reward; and a third group, the chance to enter a lottery to win £1,000. Patients in the two incentive groups were actually less likely to attend their appointments than those who received the standard invitation. The reasons for this unexpected result were not clear, but all the patients involved were from relatively deprived groups with a history of non-attendance. They were also younger than average and likely to have no apparent symptoms, which may reduce motivation to attend. The researchers also suggested that the offer of an incentive may cause a negative reaction, if the recipient believes that the screening must be unpleasant if they have to be paid to do it. This is supported by the finding that the lottery offer – to win a much larger sum – was associated with the lowest levels of attendance.
Financial incentives may be useful for supporting smoking cessation in the general population, although there are some limitations. A systematic review of 21 trials found that after six months or more, people receiving incentives were more likely to have quit than those who did not. This was supported by another review which also found that incentives continued to be effective at six months follow-up. However, there was mixed evidence about continuing effectiveness once the incentive stopped, with one of the reviews finding this was the case, but the other reporting ongoing success in only three out of 21 trials. In two US trials, quit rates were two to three times higher amongst those who received incentives, but the amounts paid were high (US$750-800). Achieving longer-term success in this case seemed to require substantial amounts which may not be feasible in practice.
Financial incentives also show potential for supporting smoking cessation in pregnancy. A review of evidence found that providing vouchers contingent on testing for smoking were effective in reducing smoking rates in late pregnancy, compared to vouchers without testing, although the studies reviewed were variable in design. In this case, linking the incentive to the desired outcome was clearly an important feature of the incentive design. Further qualitative work with participants suggested that the level of incentive, and how the incentive interacted with other elements of the intervention, were also important.
Financial incentives could play a role in encouraging adherence to anti-psychotic medications, although the advantage may not be maintained once the incentive stops. A small trial offered a £15 incentive to one group of patients for each medication taken, whilst a second group received usual care. Patients receiving the incentive were more likely to take the medication (85% vs 71%) but when the incentives stopped, adherence returned to the same level as those who had not received the incentives. The majority of patients and clinicians felt positive about the use of incentives, and the costs were relatively low.
Parental financial incentives have often been cited as a possible approach to encourage uptake of vaccinations. In fact, evidence appears to be limited, according to an NIHR systematic review, and not sufficient to show effectiveness. The review did find limited evidence that incentives might not work as well as quasi-mandatory schemes, such as preventing children from starting school until vaccinations are complete.
“I suppose it’s not about necessarily having £50.00 or the £100.00 or whatever, it’s about the recognition that you’ve done something, that you’ve achieved something.”
Anonymous, HTA study 10/31/02