We characterize a measure of social welfare for linear production economies in which individuals differ in productive skills and preferences. The key feature of our measure is that it aggregates fairness gaps, defined as the difference between the money-metric utility that the individual...

We conducted a large-scale and long lasting randomized field experiment at the donation centers of the Belgian Red Cross-Flanders to study the impact of a small extra reward for plasma donations. Donors normally receive one thank-you-coupon (worth €1.5) for a blood donation and two coupons for...