A new study by Rebecca Thornton lends further support to the idea that financial incentives should play a part in HIV prevention. In a randomised trial of over 2,000 Malawians, she gave some participants money in return for testing for HIV and finding out their results. Those receiving the cash were on average twice as likely to turn up to be tested as those left empty-handed. Even pretty small sums, amounting to a tenth of a day’s wage, had a significant effect on the likelihood of getting tested.

Unfortunately, Ms Thornton also found that being tested didn’t have much impact on sexual behaviour (though several other studies have found that knowing you’re HIV-positive makes you less likely to indulge in unsafe sex). Still, cash incentives could be used to persuade the reluctant to adopt other preventative measures, like male circumcision, condom use or, as the World Bank hopes, to find their own ways of staying negative.

H/T Chris Blattman.