Greedy or Grateful? Asking for More when Thanking Donors

Charities often send annual “thank you letters” to express gratitude to donors, but seek to defray these costs by inviting additional donations or engagement. However, the additional asks may backfire if potential donors see the thank you message as “insincere” or “manipulative.” We test this trade-off by conducting a field experiment in cooperation with a leading charity in India. We find that an explicit ask for additional donations or even a request to follow the organization on Facebook reduces giving. However, these effects are not only heterogeneous, but asymmetric by past giving behavior. Recent, frequent, and higher monetary value donors react negatively to additional asks by reducing giving, but lapsed, infrequent, and lower monetary value donors react positively by giving more. Our results highlight that findings based on purely cross-sectional experiments may offer incomplete insight. We estimate that differentially targeted ask messages based on past donation behavior, data readily available to charities, can increase donations overall by 6-11%.