How responsive are charitable donors to requests to give?

People are more likely to contribute to a charity when they are asked to. Although this so-called 'power of asking' is well-known among fundraisers, the existing literature does not pay much attention to the role of donation requests in charitable giving. This paper uses a unique survey that includes a question on whether the respondent is asked to give to estimate the causal effects of charitable solicitations on giving behavior. In order to address the endogeneity of the donation requests due to non-random solicitation of charitable donors, I link this survey to IRS data on charitable organizations and propose identifying instruments. After controlling for the endogeneity, I find that donation requests increase the propensity to give by about nineteen percentage points for those who are asked to give. This effect is robust under different specifications and with different sets of instruments, and is much larger than the estimates from univariate models, which assume that charitable solicitations are exogenous. I argue that this result is counterintuitive and discuss some possible explanations.