Eliminating Uncertainty in Market Access: The Impact of New Bridges in Rural Nicaragua
研究了尼加拉瓜农村新桥梁如何消除季节性洪水导致的市场准入不确定性，发现桥梁使洪水导致的劳动收入损失（18%）完全消失，并通过一般均衡模型揭示了对劳动选择、农业投资和储蓄的间接影响，福利提升远超收入增长。
We measure the impact of increasing integration between rural villages and outside labor markets. Seasonal flash floods cause exogenous and unpredictable loss of market access. We study the impact of new bridges that eliminate this risk. Identification exploits variation in riverbank characteristics that preclude bridge construction in some villages, despite similar need. We collect detailed annual household surveys over three years, and weekly telephone followups to study contemporaneous effects of flooding. Floods decrease labor market income by 18 percent when no bridge is present. Bridges eliminate this effect. The indirect effects on labor market choice, farm investment, and savings are quantitatively important and consistent with the predictions of a general equilibrium model in which farm investment is risky, and households manage labor market risk and agricultural risk simultaneously. In the calibrated model, the increase in consumption‐equivalent welfare is substantially larger than the increase in income due to the ability to mitigate risk.