Patents and Cumulative Innovation: Causal Evidence from the Courts

We benefitted from comments by Alfonso Gambardella, John Golden, Dietmar Harhoff, Emeric Henry, Nicola Lacetera, Bhaven Sampat, David Schwartz, Carlos Serrano, Scott Stern, John Turner and Heidi Williams. Finally we thank seminar participants at the NBER 2013 Summer Institute, Ben Gurion University, Hebrew University of Jerusalem, Northwestern University, Tel Aviv University, UC Berkeley, University of Toronto, University of Texas at Austin, Tilburg University, Hitotsubashi University, University of Waterloo and Mines ParisTech. Deepa Agarwal, Faryal Ahmed, William Matcham and Jessica Zurawicki provided excellent research assistance. We are grateful for financial support from the Centre for Economic Policy at the London School of Economics and the Social Sciences and Humanities Research Council of Canada. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research.