Patents: Their Effectiveness and Role Wesley M. Cohen Carnegie Mellon University & National Bureau of Economic Research Prepared for the FTC/DOJ Hearings on Competition and Intellectual Property Law in the Knowledge-Based Economy February 20, 2002 Collaborators: Ashish Arora, Marco Ceccagnoli, Akira Goto, Akiya Nagata, Richard R. Nelson, John P. Walsh Major sources of support: Alfred P. Sloan Foundation, National Science Foundation, Center for Global Partnership