Recently, much interest has been shown in how financial incentives can increase health enhancing behaviours.1 2 3 Two centres are studying the subject—the Centre for the Study of Incentives in Health (a joint initiative between King’s College, Queen Mary, and the London School of Economics; www.kcl.ac.uk/schools/biohealth/research/csincentiveshealth/) and the Center for Health Incentives at the University of Pennsylvania (www.med.upenn.edu/ldichi/). By encouraging healthier behaviours, it is hoped that incentives will help to contain healthcare costs and improve health. If the incentives motivate people in higher socioeconomic groups more than those in lower socioeconomic groups, however, they could exacerbate health inequalities. In the linked analysis article (doi:10.1136/bmj.b3504), Schmidt and colleagues highlight this as a potential problem in Germany, where a sickness fund rewards people for engaging in preventive activities and for minimising use …