Occupational Licensing and Psychologist Supply
利用美国心理学跨州执业契约（PSYPACT）的逐步实施，研究发现该政策使州内心理学家在线列表增加7.7%，但完全由现有从业者首次注册驱动，而非新进入者。
Does reducing interstate licensing barriers increase the supply of mental health providers? We study this question using the U.S. Psychology Interjurisdictional Compact (PSYPACT), which allows psychologists to practice across state lines via telemedicine without obtaining additional state licenses. Because interstate telemedicine entry is difficult to track using physical practice locations, we utilize data from a large mental health provider search platform, where providers choose which zipcodes they are listed in as search results. Leveraging states' staggered accession timings for identification, we find a nuanced supply response: although joining PSYPACT increases listings in a state by 7.7% within a year, the response is entirely driven by incumbent psychologists within a state listing for the first time. We find evidence consistent with incumbents responding to a perceived threat of entry, as states with ex ante high licensing costs exhibit the largest treatment effects, and incumbents choose to list in underserved, high-income areas within those states.