Hyperbolic discounting and task completion

In order to increase health risk assessment (HRA) rates at a company, employees were given no external incentives, a direct payment of $25 in a gift certificate, or were entered into a lottery of equivalent expected value if the group to which they were assigned achieved an HRA rate of at least 80%. They found that the lottery incentive yielded higher HRA rates (64%) than either the gift certificate incentive (44%) and the unincentivized case (40%), especially with lower-income employees.