Vouchers versus Lotteries: What Works Best in Promoting Chlamydia Screening? A Cluster Randomized Controlled Trial

Abstract

In this cluster randomised trial (N=1060), we tested the impact of financial incentives (£5 voucher vs. £200 lottery) framed as a gain or loss to promote Chlamydia screening in students aged 18-24 years, mimicking the standard outreach approach to student in halls of residence. Compared to the control group (1.5%), the lottery increased screening to 2.8% and the voucher increased screening to 22.8%. Incentives framed as gains were marginally more effective (10.5%) that loss-framed incentives (7.1%). This work fundamentally contributes to the literature by testing the predictive validity of Prospect Theory to change health behaviour in the field.

Optimising the use of economic interventions to increase demand for voluntary medical male circumcision in Kenya

“…Moreover, the effect of providing fixed compensation was also significantly higher than the effect of the lotterybased rewards. This noteworthy result is partially at odds with some of the theoretical rationale for using lottery-based rewards, but it is also consistent with findings from another recent study conducted in the United Kingdom that made a similar comparison of lotteries to vouchers, in this case to promote chlamydia screening among 18-to 24-yearold students (Niza et al 2014). The findings from that study also indicated that fixed vouchers (worth ₤5) were significantly more effective in increasing screening than lotterybased rewards.…”

Would you test for 5000 Shillings? HIV risk and willingness to accept HIV testing in Tanzania

“…First, starting bids were not randomized due to the survey’s administration as a paper survey. Different WTA estimates may have been obtained if starting values had been randomized [ 79 , 80 ] or if the incentive structure had involved either losses or lotteries [ 81 ]. Second, the contingent valuation questions were part of a broader study, and we did not power the data collection specifically for the analyses described in this paper.…”

Incentives in Diabetic Eye Assessment by Screening (IDEAS) trial: a three-armed randomised controlled trial of financial incentives

“…It may be hard to generalise the findings from this study to screening studies more widely, due to existing differences in findings even within the same screening behaviour, 32,33 which may depend on the country and health-care context, the population being studied and details of the incentive scheme.…”

“…[28][29][30] Other studies described incentive programmes, but did not provide a test of the impact of the incentive. 26,31 Of the relevant articles, four considered screening for chlamydia, 25,[32][33][34] three investigated breast or cervical screening, [35][36][37] five investigated tuberculosis (TB) screening or returning to collect test results, [38][39][40][41][42] two investigated work wellness programmes or private health-care plans providing preventative health-care screening, 27,43 and single papers describing incentives in diabetic retinopathy screening, 44 and glycated haemoglobin (HbA 1c ) plus cholesterol screening in patients with diabetes. 45 Three of the four studies investigating chlamydia screening observed a positive impact of incentives, 25,32,34 with evidence that vouchers were more effective than prize draws.…”

“…In studies comparing lottery incentives with fixed incentives for increasing chlamydia screening uptake, the fixed incentives were more effective than the lottery incentives at increasing uptake. 25,32 As there appears to be differences in effectiveness of lotteries in different contexts, it is not known whether or not a lottery incentive may be an effective use of limited resources in the context of increasing diabetic retinopathy screening uptake. We proposed a lottery arm where the expected value matches the incentive level offered in the other arm.…”