Results from single-donor analyses of project aid success seem to generalize pretty well across donors

Much research on foreign aid presents claims that apply to aid in general but tests these claims using data from one or a small number of donors. This makes it difficult to know if we have learned something about aid, or merely something about one donor. For example, the literature on project aid success has found that per capita GDP growth rates or Freedom House scores in recipient countries correlate with project success. However, these claims...