Mass Migration and Technological Change
研究19世纪欧洲向美国大规模移民对来源地技术变革的影响，发现移民导致创新活动增加和资本密集度提升，支持劳动力短缺诱发节约劳动型创新的理论。
Abstract This paper studies the effect of emigration on technological change in sending locations after one of the largest migration events in human history, the mass migration from Europe to the United States in the 19th century. To establish causality, we adopt an instrumental variable strategy that combines local growing-season frost shocks with proximity to emigration ports. Using data on patents, we find that emigration led to an increase in innovative activity in sending localities. Using data on capital and labor inputs in agriculture and industry, we find evidence of an increased capital intensity related to new technologies in both sectors. We argue that these results are consistent with theories of induced (labor-saving) innovation due to high labor costs following emigration.