Learning by Selling, Knowledge Spillovers, and Patents*
研究垄断企业在创新和市场竞争中，选择早期销售产品还是进行研发实验的激励，发现企业可能过度或不足实验，而专利能调节创新节奏并恢复有效实验。
We examine the incentives for experimentation in the context of innovation and market competition. A monopolist chooses whether to sell early‐stage product or perform costly scale‐up R&D. Early market participation facilitates learning about demand but invites knowledge spillovers and competitors, while R&D acts as a barrier to entry. The firm's optimal policy can exhibit both under‐ and over‐experimentation vis‐à‐vis the socially optimal policy. Patents can control the pace of innovation and restore efficient experimentation. When the surplus from R&D is large, rewarding early‐stage innovation encourages market experimentation and limits wasteful R&D investment. We offer a theory of two‐tier patent policy involving ‘petty’ patents.