The literature on aid and growth has not found a convincing instrumental variable to identify the causal effects of aid. This paper exploits an instrumental variable based on the fact that, since 1987, eligibility for aid from the International Development Association (IDA) has been based partly on whether or not a country is below a certain threshold of per capita income. The paper finds evidence that other donors tend to reinforce rather than compensate for reductions in IDA aid following threshold crossings. Overall, aid as a share of gross national income (GNI) drops about 59 % on average after countries cross the threshold. Focusing on the 35 countries that have crossed the income threshold from below between 1987 and 2010, a positive, statistically significant, and economically sizable effect of aid on growth is found. A 1 percentage point increase in the aid to GNI ratio from the sample mean raises annual real per capita growth in gross domestic product by approximately 0.35 percentage points.

中文翻译：

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援助对增长的影响：一项准实验的证据

关于援助和增长的文献还没有找到令人信服的工具变量来确定援助的因果关系。本文利用一个工具变量是基于这样一个事实，即自1987年以来，国际开发协会（IDA）的援助资格部分取决于一个国家是否低于人均收入的某个阈值。该论文发现有证据表明，其他捐助者倾向于加强而不是补偿越过门槛后IDA援助的减少。总体而言，在国家超过阈值后，援助占国民总收入（GNI）的比例平均下降约59％。以1987年至2010年之间低于收入门槛的35个国家为重点，发现援助对增长具有积极的，统计上显着的和经济上可观的影响。