PATENTABILITY, R&D DIRECTION, AND CUMULATIVE INNOVATION
研究了可专利性标准提高如何影响企业在安全与风险两个方向的研发投入，发现研发强度与标准呈倒U形（风险方向）和U形（安全方向）关系，且标准较低时研发偏向风险方向。
Abstract We present a model where firms conduct R&D in both a safe and a risky direction. As patentability standards rise, an innovation in the risky direction is less likely to receive a patent, which decreases the static incentive for new entrants to conduct risky R&D but can increase their dynamic incentive. These, together with a strategic substitution and a market structure effect, result in an inverted‐U shape in the risky direction but a U shape in the safe direction for the relationship between R&D intensity and patentability standards. R&D is biased toward (against) the risky direction under lower (higher) standards.