Demand for Giving to Multiple Charities: An Experimental Study
通过实验研究慈善机构间的竞争如何影响个人捐赠行为，发现补贴率变化对替代性慈善机构有“抢夺”效应，而对互补性慈善机构则无此效应，并计算了补贴的社会净收益。
We study how competition among charities affects individuals’ giving behavior. We characterize situations where charities benefitting substitute or complementary causes incentivize donations by offering subsidies in the form of rebates. Our theory predicts that an increase in the rebate rate offered by a given charity relative to a substitute charity will shift donations away from the substitute charity, but this “stealing” effect is not expected when complementary charities are considered. Our model further characterizes the conditions under which total donations increase with rebates. We test the model in an experimental setting, and demonstrate that the experimental results support our theoretical predictions. We derive the demand for giving as rebates vary for both substitute and complementary causes. The social net benefit of rebates is calculated by comparing campaign costs with new donations generated.