Innovative Behavioral Economics Incentives Strategies for Health

Low expected prize value.

High expected prize value.

"The incentives will increase in value when participants are found to meet the pre-specified virologic suppression criteria at 6 weeks, 3 months and 6 months.~If the virologic threshold for an incentive is missed at the 6 week or 3 month time-point, the subsequent incentive for an undetectable HIV viral load will be reset to the initial incentive value."

Travel voucher to assist with linkage to care.

Includes HIV viral load and treatment adherence counseling.

Men are informed that if they come for HIV testing, they will receive a specific prize (gain framing). The prize will be an item worth the same amount in US dollars as loss aversion and the expected value of a lottery prize. This gain-framed incentive resembles the form that incentives usually take in most studies and serves as a comparison to the lottery-based and loss-framed incentives.

The prizes are worth approximately the same amount as the fixed incentive and expected value of a lottery prize. At the time of randomization, study staff will inform the participant that he has won a prize. Staff will ask the participant to choose a specific prize from several choices, and then provide an opportunity for the participant to see the prize. Study staff will then tell participants that they will lose the prize if they do not participate in HIV testing. In this way, the incentive is framed as a loss rather than a gain, thereby leveraging loss aversion while not requiring men in very low-income settings to experience an actual loss.

"Men are entered in a lottery that offers a chance to win high-value prizes after testing for HIV at a community health campaign. Staff will emphasize that only those who come for HIV testing will be entered into the lottery and that not everyone will win a prize. Participants were informed at enrollment about the list of prizes and corresponding probabilities of winning them, in terms that are understandable to men with low numeracy (e.g., 1 in 20 rather than 5%). The probabilities of winning prizes varied between 1-5%, with higher value prizes having lower probability."

A standard gain-framed incentive arm in which participants will be offered a voucher for coming for a repeat HIV test in the future.

A loss-aversion framed incentive in which participants will be asked to voluntarily make a deposit that can be retrieved, with interest on the deposit, if they come for an HIV test in the future (i.e. for repeat testing)