The Market-Expanding Role of Regulatory Approval in Medicine
研究了FDA对后续适应症的批准如何通过认证质量和减少不确定性来扩大药品市场，发现批准后一年内新适应症的使用量增加25%，且在小规模超说明书市场中增幅更大。
Abstract Regulatory review is often seen as a barrier to innovation, increasing costs and delaying new medicines. Yet approval may also expand markets by certifying quality and reducing uncertainty. We test this by studying FDA approval for follow-on indications—uses that physicians could already prescribe “offlabel” — and find approval raises use in newly approved diseases by 25 percent within a year, with larger increases in smaller off-label markets. Subsequent approvals in the same disease yield smaller gains. Our results suggest regulatory approval of medicines expands market size by increasing demand, rather than easing insurer-imposed restrictions, revealing limits to marketbased learning.