Input Constraints and the Efficiency of Entry: Lessons from Cardiac Surgery
研究投入稀缺时自由进入对市场效率的影响，通过分析宾夕法尼亚州取消心脏手术准入管制后的市场变化，发现进入导致手术向高质量医生转移，且福利效应大致中性。
Prior studies suggest that with elastically supplied inputs free entry may lead to an inefficiently high number of firms in equilibrium. Under input scarcity, however, the welfare loss from free entry is reduced. Further, free entry may increase use of high-quality inputs, as oligopolistic firms underuse these inputs when entry is constrained. We assess these predictions by examining how the 1996 repeal of certificate-of-need (CON ) legislation in Pennsylvania affected the market for cardiac surgery in the state. We show that entry led to a redistribution of surgeries to higher quality surgeons, and that this entry was approximately welfare neutral.