Econ Papers Daily / 工作论文
不确定性下的比较优势与规模经济
Comparative Advantage and Economies of Scale under Uncertainty
摘要
We study how regional specialization patterns and welfare are affected by uncertainty and economies of scale in an open economy. We use a spatial equilibrium model with sectoral economies of scale, aggregate uncertainty, and irreversible mobility decisions made by heterogenous workers. We analytically characterize how the interactions between comparative advantage, both of workers and firms, economies of scale, and uncertainty shape specialization patterns and, hence, the gains from trade. We find empirical support for the model predictions by documenting the impact of aggregate changes in volatility of sectoral productivity on U.S. regional economies. We calibrate the model using detailed data on U.S. commuting zones and international trade, and extending hat-algebra methods to accommodate uncertainty. Quantitatively, we find that uncertainty shifts employment away from riskier sectors and locations, relative to a deterministic benchmark, lowering the U.S. aggregate gains from trade by around 20 percent. The interaction between uncertainty and scale economies brings down the benefits of specialization. For regions that would otherwise lose from trade, the presence of agglomeration forces and a more elastic labor supply mitigates those losses.
中文摘要
我们研究开放经济中不确定性和规模经济如何影响区域专业化模式与福利。我们使用一个空间均衡模型，其中包含部门规模经济、总体不确定性，以及异质性工人做出的不可逆迁移决策。我们解析地刻画了工人和企业的比较优势、规模经济与不确定性之间的相互作用如何塑造专业化模式，进而塑造贸易收益。通过记录部门生产率波动性的总体变化对美国区域经济的影响，我们找到了支持模型预测的经验证据。我们使用美国通勤区和国际贸易的详细数据校准模型，并扩展hat-algebra方法以纳入不确定性。在定量上，我们发现，相对于确定性基准，不确定性使就业从风险更高的部门和地点转移出去，使美国总体贸易收益降低约20%。不确定性与规模经济之间的相互作用降低了专业化的收益。对于原本会从贸易中受损的地区，集聚力量的存在和更富弹性的劳动供给缓解了这些损失。