The Forgotten Rationale for Policy Reform: The Productivity of Investment Projects
利用世界银行资助项目的经济回报率，研究国家政策和宏观环境如何影响投资生产率，发现扭曲政策会显著降低项目回报，且任何项目类型都无法免受其影响。
Using economic rates of return from World Bank-funded investments, we investigate how country characteristics and policies that influence aggregate performance affect investment productivity. Controlling for other characteristics, countries with undistorted (distorted) macroeconomic, exchange rate, trade, and pricing policies have highly productive (unproductive) investments. No type of project—in tradable or nontradable sectors—can be “insulated” from poor policies, where returns on investments are about ten percentage points lower Productivity increases when policies improve within a country. Projects are also affected, nonlinearly, by the size of the public investment program where policies are undistorted. The results offer new evidence on benefits from policy reform and challenge conventional cost-benefit analysis.