Doctoral Dissertation Research in Economics: Increasing Charitable Donations Using Subsidies: Theory and Experiments

这项研究考察了捐赠补贴如何以及在多大程度上可以用来增加慈善捐款。美国政府利用税法为捐赠者提供补贴，对符合条件的捐赠免税，有效地为捐赠者提供等于其边际税率的退税。这些补贴降低了捐赠者面临的捐赠价格。补贴捐款的另一种方法是“匹配”捐赠者的捐款。这是慈善机构使用的最常见的补贴类型。通常，慈善机构与一位富有的捐赠者协调，后者同意以某个预定的比率匹配对慈善机构的捐赠。例如，捐赠者向慈善机构提供的每一美元，富有的捐赠者可能会同意提供额外的一美元，使慈善机构收到的总捐款达到两美元。与回扣一样，配对降低了捐赠者面临的捐赠价格。事实上，对于任何给定的回扣，都存在相应的匹配率，从而产生相同的赠送价格。如果回扣和比赛产生的价格与赠送的价格相同，那么它们就被称为价格相等。与直觉相反的是，之前的研究发现，捐赠者对同等价格的回扣和匹配的反应并不相同。相反，在保持捐赠价格不变的情况下，捐赠明显比回扣对比赛的反应更快。这意味着，重组美国税收体系，提供比赛补贴，而不是回扣补贴，可能会大幅增加慈善捐款。然而，这项研究提出了新的证据，表明匹配可能不会像之前的研究中报告的那样，在一定程度上超过回扣，特别是在税收方面。通过新的实验，研究人员考察了个人对捐赠补贴的反应，以及行为如何根据筹款人的特征发生变化，为有兴趣增加捐款的政策制定者和慈善机构提供了有价值的指导。本研究分为两个项目。第一个项目使用实验室实验比较回扣价格弹性和匹配价格弹性。之前在实验室环境中比较回扣和匹配的研究使用了实验设计，在这种设计中，等价回扣和匹配产生了不同的预算集，潜在地偏向了价格弹性估计。在这项研究中，研究人员开发了一种新颖的实验设计，其中回扣和匹配在一个税收框架内呈现，而价格等值回扣和匹配的预算设置是相同的。本实验解决了以往研究中存在的预算设置问题，并与税收政策直接相关。还进行了其他实验，以进一步研究推动捐助者对补贴作出反应的潜在机制，并对实验设计对观察到的行为产生影响的程度提供见解。第二个项目从理论和实验两方面调查筹款特征的差异如何影响捐赠者对匹配率变化的反应。开发了一个结合筹款特征的捐赠理论模型，允许匹配价格弹性在不同的筹款活动中有所不同。通过两个实验对模型的理论预测进行了验证。第一个实验外在地改变了捐赠者的捐献匹配的概率。第二个实验间接地通过外部变化的筹款人特征来改变匹配的概率。这个奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This research examines how, and to what extent, subsidies for giving can be used to increase charitable donations. The U.S. government provides subsidies for giving using the tax code, by making qualifying donations tax-exempt, effectively providing donors with a rebate equal to their marginal tax rate. These subsidies lower the price of giving faced by donors. An alternative method of subsidizing donations is to “match” donors’ contributions. This is the most common type of subsidy used by charities. Typically, charities coordinate with a wealthy donor who agrees to match donations to the charity at some predetermined rate. For example, for every dollar a donor provides to the charity, the wealthy donor may agree to provide an additional dollar, making the total donation received by the charity two dollars. Like rebates, matches lower the price of giving faced by donors. In fact, for any given rebate, there is a corresponding match rate that produces the same price of giving. If a rebate and a match produce the same price of giving, they are said to be price equivalent. Counterintuitively, previous research has found that donors do not respond equally to price-equivalent rebates and matches. Instead, holding the price of giving constant, donations are significantly more responsive to matches than rebates. This implies that restructuring the U.S. tax system to provide match subsidies rather than rebate subsidies could significantly increase charitable donations. However, this research presents new evidence suggesting that matches may not outperform rebates to the extent reported in previous studies, particularly in the context of taxes. Using novel experiments, the researchers examine how individuals respond to subsidies for giving and how behavior varies depending on the characteristics of the fundraiser, providing valuable guidance to policymakers and charities interested in increasing donations. This research is separated into two projects. The first project compares rebate- and match-price elasticities using laboratory experiments. Previous studies comparing rebates and matches in laboratory settings have used experimental designs in which price-equivalent rebates and matches produce disparate budget sets, potentially biasing price-elasticity estimates. In this study the investigators develop a novel experimental design in which rebates and matches are presented within a tax framework and the budget sets for price-equivalent rebates and matches are identical. This experiment resolves the budget set issue present in previous studies and is directly relevant for tax policy. Additional experiments are conducted to further examine the underlying mechanisms driving donors’ responses to subsidies, as well as to provide insights into the extent to which experimental design affects observed behavior. The second project investigates, both theoretically and experimentally, how differences in fundraiser characteristics affect how donors respond to changes in the match rate. A theoretical model of giving incorporating fundraiser characteristics is developed, allowing for match-price elasticities to vary across heterogeneous fundraisers. Two experiments are used to test the theoretical predictions of the model. The first experiment exogenously changes the probability with which a donor’s donation is matched. The second experiment indirectly varies the probability of being matched by exogenously changing characteristics of the fundraiser.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.