Eliminating Uncertainty in Market Access: The Impact of New Bridges in Rural Nicaragua
Econometrica · 2020 · Wyatt J. Brooks、Kevin Donovan
中文摘要
我们测度了农村村庄与外部劳动力市场一体化程度提高所带来的影响。季节性突发性洪水会导致村庄无法进入市场，这种市场可达性的丧失具有外生性且不可预测。我们研究了消除这一风险的新建桥梁所产生的影响。识别利用了河岸特征的差异：尽管建桥需求相似，但这些特征使部分村庄无法修建桥梁。我们连续三年收集了详细的年度家庭调查数据，并每周开展电话跟踪调查，以研究洪水的同期效应。在没有桥梁的情况下，洪水使劳动力市场收入下降18%。桥梁消除了这一效应。桥梁对劳动力市场选择、农业投资和储蓄的间接效应在数量上具有重要性，且与一个一般均衡模型的预测一致；在该模型中，农业投资具有风险，家庭同时管理劳动力市场风险和农业风险。在校准后的模型中，由于能够缓解风险，消费等价福利的增幅远大于收入的增幅。
Abstract
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.