"Pay them if it works": discrete choice experiments on the acceptability of financial incentives to change health related behaviour.

The use of financial incentives to change health-related behaviour is often opposed by members of the public. We investigated whether the acceptability of incentives is influenced by their effectiveness, the form the incentive takes, and the particular behaviour targeted. We conducted discrete choice experiments, in 2010 with two samples (n = 81 and n = 101) from a self-selected online panel, and in 2011 with an offline general population sample (n = 450) of UK participants to assess the acceptability of incentive-based treatments for smoking cessation and weight loss. We focused on the extent to which this varied with the type of incentive (cash, vouchers for luxury items, or vouchers for healthy groceries) and its effectiveness (ranging from 5% to 40% compared to a standard treatment with effectiveness fixed at 10%). The acceptability of financial incentives increased with effectiveness. Even a small increase in effectiveness from 10% to 11% increased the proportion favouring incentives from 46% to 55%. Grocery vouchers were more acceptable than cash or vouchers for luxury items (about a 20% difference), and incentives were more acceptable for weight loss than for smoking cessation (60% vs. 40%). The acceptability of financial incentives to change behaviour is not necessarily negative but rather is contingent on their effectiveness, the type of incentive and the target behaviour.