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

这项研究探讨了如何以及在多大程度上，捐赠补贴可以用来增加慈善捐款。美国政府为使用税法的捐赠提供补贴，使合格的捐赠免税，有效地为捐赠者提供相当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。另一种补贴捐款的方法是"匹配"捐助者的捐款。这是慈善机构使用的最常见的补贴类型。通常情况下，慈善机构与一位富有的捐赠者协调，后者同意以某种预定的比率将捐赠与慈善机构相匹配。例如，对于捐赠者向慈善机构提供的每一美元，富有的捐赠者可以同意提供额外的一美元，使得慈善机构收到的总捐赠为两美元。像回扣一样，匹配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，都有一个相应的匹配率，产生相同的给予价格。如果回扣和匹配产生相同的给予价格，它们被称为价格等价。与直觉相反的是，先前的研究发现，捐赠者对等价回扣和匹配的反应并不相同。相反，保持捐赠的价格不变，捐赠对匹配的反应要比回扣大得多。这意味着，重组美国税收体系，提供匹配补贴而不是退税补贴，可以显著增加慈善捐款。然而，这项研究提出了新的证据表明，比赛可能不会超过回扣的程度在以前的研究报告，特别是在税收的背景下。通过新的实验，研究人员研究了个人如何对捐赠补贴做出反应，以及行为如何根据筹款人的特征而变化，为有兴趣增加捐赠的政策制定者和慈善机构提供了有价值的指导。这项研究分为两个项目。第一个项目比较回扣和匹配价格弹性使用实验室实验。先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，其中价格等效回扣和匹配产生不同的预算集，可能会使价格弹性估计产生偏差。在这项研究中，研究人员开发了一种新的实验设计，其中回扣和比赛中提出的税收框架和预算设置的价格等价回扣和比赛是相同的。这个实验解决了以前研究中存在的预算问题，并与税收政策直接相关。进行了额外的实验，以进一步研究驱动捐助者的反应补贴的基本机制，以及提供洞察实验设计影响观察到的行为的程度。第二个项目调查，从理论和实验上，筹款人的特点如何影响捐助者如何应对匹配率的变化的差异。一个理论模型，给予结合筹款人的特点，允许匹配的价格弹性不同异质筹款人。两个实验被用来测试模型的理论预测。第一个实验外源性地改变了捐赠者的捐赠被匹配的概率。第二个实验间接地改变了被筹款人的外部变化特征匹配的概率。这个奖项反映了NSF的法定使命，并被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

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.