Labor Supply and Directed Technical Change: Evidence from the Termination of the Bracero Program in 1964
利用1964年美国终止与墨西哥的Bracero协议导致的农业劳动力供给负冲击，研究发现该冲击显著增加了受影响作物的技术创新，尤其集中在劳动密集型生产任务上，但农场主整体福利受损。
This paper studies the impact of labor supply on the creation of new technology, exploiting a large exogenous shock to the US agricultural labor supply caused by the termination of the Bracero agreements between the US and Mexico at the end of 1964. Using a text-search algorithm allocating patents to crops, I show a negative labor-supply shock induced a sharp increase in innovation in technologies related to more affected crops. The effect is stronger for technology related to labor-intensive production tasks. Farm-value dynamics indicate that, despite the positive technology reaction, the policy change was undesirable for farm owners.