Reward blood donors for showing up, not giving — incentives without lying

Ars Technica reported in May 2013 on a Science paper by Nicola Lacetera, Mario Macis and Robert Slonim arguing that WHO's four-decade advice against economic incentives for blood donors was 'fundamentally flawed'. The FDA prohibits paying blood donors, so incentives are structured as gifts — gift certificates, CDs, T-shirts, lottery tickets — and the paper's synthesis of recent studies found nearly any incentive increases donations, with higher-value rewards working better.

The numbers: a 5-franc lottery ticket in Switzerland raised donations about 5 percentage points; a $10 gift card raised them 7 percentage points in the US; a day of paid leave in Italy raised donations 40 percent over a year. The only tested incentive that failed was a free cholesterol test. Crucially, follow-up testing found not a single incentive affected the safety of the blood supply.

The design detail that made it safe: in every study the reward was offered for simply showing up to donate, not for giving blood — so there was no reason to lie about drug use, medication or health history to walk away with a gift card. The authors cautioned that incentives had been tested only once or occasionally, mostly in wealthy nations, and that donors surprised with unexpected rewards sometimes donated less afterwards — but carefully chosen rewards could safely smooth shortages in emergencies.

Offer the reward for showing up to donate, never for the blood itself — donors keep no reason to lie at screening, so the supply stays safe while donations rise

It separates the incentive from the information: screening answers determine safety, so rewards are placed upstream where honesty costs the donor nothing.

It respects the letter of the law — no one is paid for blood, they are thanked for attendance — which is why the FDA prohibition stays intact.

The evidence is quantified across countries and designs (lottery, gift card, paid leave), not a single anecdote, and published in Science.

The failed control — free cholesterol tests — shows the mechanism needs real value to the donor, not just a health halo.

Incentive design can defuse its own moral hazard: attach the reward to an upstream act that carries no informational stakes, and the forbidden transaction never happens.

The paper's case was conditional: incentives were a tool for emergencies and seasonal shortages, not a universal replacement for empathy-based appeals, and long-term effects (including whether unexpected rewards crowd out intrinsic motivation) remained open questions. The immediate claim stood: rewards raised donations and left safety metrics untouched, contradicting the WHO guidance's core worry.