Occupational Licensing and Maternal Health: Evidence from Early Midwifery Laws
利用1900-1940年间美国各州和市镇助产法实施时间和细节的差异，研究发现要求助产士获得许可使孕产妇死亡率降低7%-8%，并可能小幅降低婴儿死亡率，为职业许可改善消费者健康提供了迄今最强证据。
Exploiting variation across states and municipalities in the timing and details of midwifery laws introduced during the period 1900–1940 and using data assembled from various primary sources, we find that requiring midwives to be licensed reduced maternal mortality by 7%–8% and may have led to modest reductions in infant mortality. These estimates represent the strongest evidence to date that licensing restrictions can improve the health of consumers and are directly relevant to ongoing policy debates on the merits of licensing midwives.