"A Theory of Tacit Collusion" January 2012. Paper

"Corporate Leniency Programs when Firms have Private Information: The Push of Prosecution and the Pull of Pre-emption" November 2011. Paper

"Signaling and Tacit Collusion in an Infinitely Repeated Prisoners' Dilemma" (joint with Wei Zhao), May 2011. Paper

"The Impact of a Corporate Leniency Program on Antitrust Enforcement and Cartelization" (joint with Myong-Hun Chang), April 2010. Paper This research is supported by NSF Grant SES-0516943. 

"Private Monitoring and Communication in Cartels: Explaining Recent Collusive Practices" (joint with Andrzej Skrzypacz), American Economic Review, October 2011. Paper Appendix This research is supported by NSF Grant SES-0516943.

"Posted Pricing as a Plus Factor," Journal of Competition Law and Economics, March 2011. PDF Copy

"When is an Antitrust Authority not Aggressive Enough in Fighting Cartels?," International Journal of Economic Theory (A Special Issue on Game Theory and Industrial Organization in Honor of James Friedman), March 2011. PDF Copy This research is supported by NSF Grant SES-0516943.

"Comment on 'Antitrust Sanctions',"(by Douglas Ginsburg and Joshua Wright), Competition Policy International, Autumn 2010. PDF Copy Link to Special Issue on Cartel Sanctions

"Stockpiling Anti-Viral Drugs for a Pandemic: The Role of Manufacturer Reserve Programs," (joint with Edbert Hsu), Journal of Health Economics, May 2010. PDF Copy

"Endogenous Cartel Formation with Heterogeneous Firms," (joint with Iwan Bos), RAND Journal of Economics, Spring 2010. PDF Copy This research is supported by NSF Grant SES-0516943.

"Modelling the Birth and Death of Cartels with an Application to Evaluating Antitrust Policy," (joint with Myong-Hun Chang), Journal of the European Economic Association, December 2009. PDF Copy This research is supported by NSF Grant SES-0516943.

"Avoiding Market Dominance: Product Compatibility in Markets with Network Effects," (joint with Jiawei Chen and Ulrich Doraszelski), RAND Journal of Economics, Autumn 2009. PDF Copy

"Optimal Corporate Leniency Programs," Journal of Industrial Economics, June 2008. PDF Copy This research is supported by NSF Grant SES-0516943.

"Detecting Cartels," in Handbook in Antitrust Economics, Paolo Buccirossi, editor (MIT Press), 2008. PDF Copy This research is supported by NSF Grant SES-0209486.

"Behavioral Screening and the Detection of Cartels," in European Competition Law Annual 2006: Enforcement of Prohibition of Cartels, Claus-Dieter Ehlermann and Isabela Atanasiu, eds., Hart Publishing, 2007. PDF Copy This research is supported by NSF Grant SES-0516943.

"Collusion under Monitoring of Sales," (joint with Andy Skrzypacz), RAND Journal of Economics, Summer 2007. PDF copy This research is supported by NSF Grant SES-0516943.

"Innovators, Imitators, and the Evolving Architecture of Problem-Solving Networks," (joint with Myong-Hun Chang), Organization Science, July 2007. PDF Copy

"Handedness and Earnings," (joint with Robert Moffitt and Christopher Ruebeck), Laterality, 2007. NBER Working Paper 12387 PDF Copy Washington Post (article) U.S. News and World Report (article) NPR Marketplace (interview) Playboy ("Money in the Hand")

"The Impact of the Corporate Leniency Program on Cartel Formation and the Cartel Price Path," (joint with Joe Chen), in The Political Economy of Antitrust, V. Ghosal and J. Stennek, eds., Elsevier, 2007. PDF Copy This research is supported by NSF Grant SES-0516943.

"Equilibrium Pricing in a (Partial) Search Market: The Shopbot Paradox," (joint with Megan Leahey), Economics Letters, January 2007. PDF Copy

"Cartel Pricing Dynamics with Cost Variability and Endogenous Buyer Detection" (joint with Joe Chen), International Journal of Industrial Organization, November 2006. PDF Copy This research is supported by NSF Grant SES-0209486.

"How Do Cartels Operate?," Foundations and Trends in Microeconomics, August 2006. Purchase or download This research is supported by NSF Grant SES-0516943.

"Agent-Based Models of Organizations" (joint with Myong-Hun Chang) in Handbook of Computational Economics II: Agent-Based Computational Economics, Kenneth L. Judd and Leigh Tesfatsion, editors, 2006. PDF Copy Handbook

"Collusive Game Solutions via Optimization" (joint with Benjamin Hobbs, Jong-Shi Pang, Andrew Liu, and Grant Roch), Mathematical Programming, B, July 2005. PDF Copy This research is supported by NSF Grant ECS-0224817.

"Optimal Cartel Pricing in the Presence of an Antitrust Authority," International Economic Review, February 2005. PDF Copy This research is supported by NSF Grant SES-0209486.

"Co-Evolution of Firms and Consumers and the Implications for Market Dominance" (joint with Myong-Hun Chang), Journal of Economic Dynamics and Control, January 2005. PDF Copy This research is supported by NSF Grant SES-0078752.

"Discovery and Diffusion of Knowledge in an Endogenous Social Network" (joint with Myong-Hun Chang), American Journal of Sociology, January 2005. PDF Copy This research is supported by NSF Grant SES-0078752.

"Cartel Pricing Dynamics in the Presence of an Antitrust Authority," RAND Journal of Economics, Winter 2004. PDF Copy Supplemental Appendix This research is supported by NSF Grant SES-0209486.

"Post-Cartel Pricing during Litigation," Journal of Industrial Economics, December 2004 JIE PDF Copy Non-technical version (Global Competition Litigation Review, forthcoming) GCLR PDF Copy This research is supported by NSF Grant SES-0209486.

"Multi-Market Competition, Consumer Search, and the Organizational Structure of Multi-Unit Firms"(joint with Myong-Hun Chang), Management Science, April 2003. PDF Copy This research is supported by NSF Grant SES-0078752.

"Rigidity and Flexibility in Social Systems: Transitional Dynamics" in Computational Models in Political Economy, K. Kollman, J. Miller, and S. Page, eds., The MIT Press, 2003. PDF Copy Animation This research is supported by NSF Grant SES-0000679.

"Some Implications of Antitrust Laws for Cartel Pricing," Economics Letters, June 2003. PDF Copy This research is supported by NSF Grant SES-0209486.

"Decentralized Business Strategies in a Multi-Unit Firm" (joint with Myong-Hun Chang), Annals of Operations Research, January 2002. PDF Copy This research is supported by NSF Grant SES-0078752.

"Comment on 'Reducing Buyer Search Costs: Implications for Electronic Marketplaces'," Management Science, December 2001 PDF Copy

"A Simple Game-Theoretic Explanation for the Relationship between Group Size and Helping," Journal of Mathematical Psychology, April 2001. PDF Copy

"Centralization vs. Decentralization in a Multi-Unit Organization: A Computational Model of a Retail Chain as a Multi-Agent Adaptive System" (joint with Myong-Hun Chang), Management Science, November 2000. PDF Copy Santa Fe Institute, Working Paper 00-02-10

"A Theory of Rigid Extremists and Flexible Moderates with an Application to the U.S. Congress," (joint with S. Brock Blomberg), American Economic Review, June 2000. PDF Copy This research is supported by NSF Grant SES-9708910.

"Progressive Ambition, Electoral Selection, and the Creation of Ideologues," Economics of Governance, Vol. 1, Issue 1, 2000. PDF Copy This research is supported by NSF Grant SES-9708910.

"The Equilibrium Level of Rigidity in a Hierarchy," Games and Economic Behavior, August 1999. PDF Copy This research is supported by NSF Grant SES-9708910.

"Rigidity of Social Systems" Journal of Political Economy, February 1999. PDF Copy This research is supported by NSF Grant SES-9708910. 
Animation: View proportion of agents using a flexible rule as w ranges from 1 to 0 (Figure 4). k ranges from 5 to 25 and b ranges from .5 to .9. Viewing animation requires the QuickTime viewer.

"The Social Selection of Flexible and Rigid Agents," American Economic Review, 88 (March 1998), 63-82. PDF Copy

"Organizational Structure and Firm Innovation in a Retail Chain," (co-authored with Myong-Hun Chang), Computational and Mathematical Organization Theory, 3 (1998), 267-288. PDF Copy.

180.215 Game Theory and the Social Sciences:
Game theory is one of the few mathematical tools developed for the purpose of understanding social phenomena. This course provides an introduction to game theory with an emphasis on applications, in economics, political science, business, military science, history, biology, theology and recreation. The required mathematical background is minimal - high school algebra is sufficient. Prerequisites: A sincere intent to attend class on a regular basis and the ability to engage in a little mathematics without having an anxiety attack.
Course syllabus

180.671 Industrial Organization:
This course explores firm and industry behavior with an emphasis on markets characterized by imperfect competition. The central issues addressed concern the determinants of the intensity of competition, entry and exit, industry dynamics, and market dominance.
Course Web Page

Bayard Wickliffe Heath Memorial Lecture (University of Florida Levin College of Law), March 2012, "Game-Theoretic Ruminations on Section 1 of the Sherman Act," Slides

Día de la Competencia 2011 (Santiago), October 2011. Lecture: "Economic Analysis and the Fight Against Cartels: Developing an Effective Screening Program", Slides, Photo

European Association for Research in Industrial Economics Meetings(Stockholm), September 2011.

Conference on Antitrust Enforcement in the Presence of Leniency Programs (Bergen), August 2011. Lecture: "The Battle Against Hard Core Cartels: Measurement and Incentive Challenges" Slides Article

European Summer School in Competition & Regulation (Rhodes), June/July 2011. Course on Collusive Practices: Slides

American Economic Association Meetings (Denver), January 2011. Virtual Corporate Reality: Simulated Oligopoly to Enhance Student Learning

Tercer Taller de Organización Industrial(Zapallar, Chile), December 2010.

Avances en Políticas y Legislación Pro Competencia (Santiago), December 2010. Lecture: "Leniency Programs: Past Experiences and Future Challenges" Slides

Distinguished Visiting Scholar Mini-Course: "Game Theory" (U. of Cincinnati), October 2010. Slides

Third Annual Searle Research Symposium on Antitrust Economics and Competition Policy(Northwestern University), September 2010.

European Summer School in Competition & Regulation(Crete), July 2010. Course on Collusive Practices.

Universidad Carlos III de Madrid - Summer School in Economics(Madrid), June 2010. Course on Collusion and Cartels: Brochure

International Industrial Organization Conference(Vancouver), May 2010.

Justus-Liebig-Universtät Giessen: "Lectures on Cartels" (Germany), January 2010. Giessener Anzeiger Photo

Economic Developments in European Competition Policy (Brussels), December 2009. Lecture: "Screening for Cartels: The Next Step in Enforcement" Slides

8th Annual Duke/Northwestern/Texas IO Theory Conference(Evanston), November 2009.

3rd Conference on the Research Network on Innovation and Competition Policy: "Competition Policy and Innovation: Where Do We Stand?" (Vienna), October 2009. Keynote Lecture: "Communication and Monitoring in Cartels: Explaining the Stability of the Citric Acid, Lysine, and Vitamins Cartels" Slides

3rd Annual Competition Commission, Competition Tribunal and Mandela Institute Conference on Competition Law, Economics and Policy (Pretoria), September 2009. Lecture: "Screening for Cartels at Public Procurement Auctions" Slides

European Summer School and Conference in Competition & Regulation (Crete), July 2009. Conference Policy Lecture: "Investigating the Investigators: What Does a Competition Authority Maximize?" Slides Photo

Centre for Competition Policy (U. of East Anglia) Fifth Annual Conference - Cartels and Tacit Collusion(Norwich, England), June 2009.

Helsinki Center of Economic Research - Cartels and Collusion(Helsinki), June 2009.

Midwest Teaching Symposium(Cincinnati), April 2009.

International Industrial Organization Conference(Boston), April 2009.

Amsterdam Center for Law and Economics (U. of Amsterdam) Fifth Annual Competition & Regulation Meeting - To Enforce and Comply: Incentives inside Corporations and Agencies (Amsterdam), March 2009. Keynote Lecture: "Evaluating and Understanding a Competition Authority" Slides Photo

Winter Econometric Society Meetings(San Francisco), January 2009.

First Annual FTC Microeconomics Conference(Washington, D.C.), November 2008.

15th WZB Conference on Markets and Politics and the 2nd Conference of the Research Network on Innovation and Competition Policy (RNIC): "Deterrence in Competition Policy" (Berlin), October 2008. Keynote Lecture: "Antitrust Enforcement and Corporate Leniency Programs" Slides

UBC Summer Conference on Industrial Organization(Whistler, BC), July 2008.

Bates White Fifth Annual Antitrust Conference(Washington, D.C.), June 2008.

European Association for Research in Industrial Economics Meetings(Valencia), September 2007.

European Summer Symposium in Economic Theory (Gerzensee, Switzerland), July 2007. Slides

1st Conference of the Research Network on Innovation and Competition Policy: Modern Approaches in Competition Policy (Mannheim, Germany), May 2007. Keynote Lecture: "The Design, Practice, and Performance of Corporate Leniency Programs" Slides Poster

International Industrial Organization Conference (Savannah), April 2007.

European Association for Research in Industrial Economics Meetings (Amsterdam), August 2006. Keynote Lecture: "Anatomy of a Cartel Price Path" Slides Poster

EU Competition Law and Policy Workshop: Enforcement of Prohibition of Cartels (Florence), June 2006. Paper

International Industrial Organization Conference(Boston), April 2006.

Towards an Effective Implementation of New Competition Policy (Tokyo), January 2006. Slides Paper Newspaper article (NIKKEI)

Csef-Igier Symposium on Economics and Institutions (Capri)- June/July 2005. Keynote Lecture: "The Collusion Chasm:Reducing the Gap Between Antitrust Practice and Industrial Organization Theory" Slides