Fair Ranking Design for Medical Crowdfunding

Abstract

Medical crowdfunding platforms promise to help those unable to afford healthcare, yet campaigns by less socially connected individuals systematically raise fewer donations. We study whether this inequality reflects unconnected donors' limited awareness-rather than their preferences-and whether platform ranking design can mitigate it. Using data from Qingsongchou, China's largest medical crowdfunding platform, which implements a policy to randomly assign promotion timing and ranking, we show that a front-page promotion leads to a 257% increase in donations, and that the effect is concentrated among donors unconnected to the campaigner. We estimate a structural model of donation choice under limited consideration and find that 64% of donors consider at most the top four ranked campaigns. Counterfactual simulations show that equality-oriented rankings, which prioritize campaigns with fewer social connections, meaningfully reduce inequality in donation outcomes with only small costs to platform revenue. However, a donor-surplus-maximizing ranking would significantly increase both revenue and inequality, creating a tradeoff in platform ranking design.

Keywords: Ranking Design, Limited Consideration, Donations, Crowdfunding

JEL Classification: D83, D47, C51, L86, D63