Regulatory Growth Theory Danxia Xie Tsinghua University December 31, 2017 Abstract This research explores and quantifies the downside of innovations, especially the negative externality of an innovation interacting with the stock of existing innovations. Using two novel datasets, I find that the number of varieties of innovation risks is quadratic in the varieties of innovations that caused them. Based on this new empirical fact, I develop a Regulatory Growth Theory: a new growth model with innovation-induced risks and with a regulator. I model both the innovation risk generating structure and the regulator’sendoge- nous response. This new theory can help to interpret several empirical puzzles beyond the explanatory power of existing models of innovations: (1) skyrocketing expected R&D cost per innovation and (2) exponentially increasing regulation over time. Greater expenditures on regulation and corporate R&D are required to assess the net benefit of an innovation because of “Risk Externality”: negative interaction effects between innovations. The rise of regulation versus litigation, and broader implications for regulatory reform are also discussed. Address: Institute of Economics, Tsinghua University, China. The author’s e-mail address is
[email protected]. I am grateful to Gary Becker, Casey Mulligan, Randy Kroszner, Tom Philipson, and Eric Posner for invaluable advice. Also thank Ufuk Akcigit, Olivier Blanchard, Will Cong, Steve Davis, Jeffrey Frankel, Matt Gentzkow, Yehonatan Givati, Michael Greenstone, Lars Hansen, Zhiguo He, Chang- Tai Hsieh, Chad Jones, Greg Kaplan, John List, Bob Lucas, Joel Mokyr, Roger Myerson, Andrei Shleifer, Hugo Sonnenschein, Nancy Stokey, and Hanzhe Zhang for very helpful suggestions and discussions. An early version was presented at Econometric Society 2015 World Congress, Montreal.