Dynamic Equilibrium in the US Prescription Drug Market After Patent Expiration
In this paper I formulate and estimate an empirical dynamic oligopoly model that incorporates consumer learning, consumer heterogeneity and forward-looking firms. I apply this model to explain the evolution of pharmaceutical markets after patent expiration, and to address its related policy issues. I develop a practical method to estimate the parameters of the model that does not require finding instruments or solving the equilibrium model. Using this new method and a data set detailing the evolution of prices and market shares for 31 chemical entities from 1984-1990, I estimate the distribution of consumer preferences that determine how consumers evaluate risks, perceived attribute levels, and prices when choosing among brand-name originals and generics. I also design and program a backward induction algorithm to numerically solve the equilibrium model with different market structures. This computer program, together with the estimated preference parameter values and calibrated cost parameter values, are used to select a market structure that best fits the data, and the selected market structure is applied to analyze the firms' strategic behavior. According to the preliminary estimate results based on data from two markets, flurazepam and temazepam, I find that learning plays an important role in explaining the slow increase in market share for generic drugs. I also demonstrate that consumer heterogeneity has the potential to explain the pricing pattern that brand-name prices increase in response to generic entry. Finally, the model will be used to quantify the benefits of introducing generic drugs and to simulate the impact of various new public policies, including restricting the price for brand-name originals below some arbitrary level, reducing the average approval time for marketing generic drugs, and changing the cost of obtaining such approval.
|Date of creation:||01 Aug 2000|
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- Ariel Pakes, 1984.
"Patents as Options: Some Estimates of the Value of Holding European Patent Stocks,"
NBER Working Papers
1340, National Bureau of Economic Research, Inc.
- Pakes, Ariel S, 1986. "Patents as Options: Some Estimates of the Value of Holding European Patent Stocks," Econometrica, Econometric Society, vol. 54(4), pages 755-84, July.
- Berndt, Ernst R & Griliches, Zvi & Rosett, Joshua G, 1993.
"Auditing the Producer Price Index: Micro Evidence from Prescription Pharamceutical Preparations,"
Journal of Business & Economic Statistics,
American Statistical Association, vol. 11(3), pages 251-64, July.
- Ernst R. Berndt & Zvi Griliches & Joshua G. Rosett, 1992. "Auditing the Producer Price Index: Micro Evidence From Prescription Pharmaceutical Preparations," NBER Working Papers 4009, National Bureau of Economic Research, Inc.
- Sara Ellison Fisher & Iain Cockburn & Zvi Griliches & Jerry Hausman, 1997.
"Characteristics of Demand for Pharmaceutical Products: An Examination of Four Cephalosporins,"
RAND Journal of Economics,
The RAND Corporation, vol. 28(3), pages 426-446, Autumn.
- Ellison, S & Cockburn, I & Griliches, A & Hausman, J, 1996. "Characteristics of Demand for Pharmaceutical Products : an Examination of four Cephalosporins," Working papers 96-24, Massachusetts Institute of Technology (MIT), Department of Economics.
- James J. Heckman, 1981. "Heterogeneity and State Dependence," NBER Chapters, in: Studies in Labor Markets, pages 91-140 National Bureau of Economic Research, Inc.
- Olley, G Steven & Pakes, Ariel, 1996.
"The Dynamics of Productivity in the Telecommunications Equipment Industry,"
Econometric Society, vol. 64(6), pages 1263-97, November.
- George S Olley & Ariel Pakes, 1992. "The Dynamics Of Productivity In The Telecommunications Equipment Industry," Working Papers 92-2, Center for Economic Studies, U.S. Census Bureau.
- G. Steven Olley & Ariel Pakes, 1992. "The Dynamics of Productivity in the Telecommunications Equipment Industry," NBER Working Papers 3977, National Bureau of Economic Research, Inc.
- Heckman, James & Singer, Burton, 1984. "A Method for Minimizing the Impact of Distributional Assumptions in Econometric Models for Duration Data," Econometrica, Econometric Society, vol. 52(2), pages 271-320, March.
- Ernst R. Berndt & Linda Bui & David Reiley & Glen Urban, 1994.
"The Roles of Marketing, Product Quality and Price Competition in the Growth and Composition of the U.S. Anti-Ulcer Drug Industry,"
NBER Working Papers
4904, National Bureau of Economic Research, Inc.
- Ernst R. Berndt & Linda T. Bui & David H. Lucking-Reiley & Glen L. Urban, 1996. "The Roles of Marketing, Product Quality, and Price Competition in the Growth and Composition of the U.S. Antiulcer Drug Industry," NBER Chapters, in: The Economics of New Goods, pages 277-328 National Bureau of Economic Research, Inc.
- Keane, Michael P, 1994. "A Computationally Practical Simulation Estimator for Panel Data," Econometrica, Econometric Society, vol. 62(1), pages 95-116, January.
- Gary S. Becker & Kevin M. Murphy, 1993. "A Simple Theory of Advertising as a Good or Bad," The Quarterly Journal of Economics, Oxford University Press, vol. 108(4), pages 941-964.
- McFadden, Daniel, 1989.
"A Method of Simulated Moments for Estimation of Discrete Response Models without Numerical Integration,"
Econometric Society, vol. 57(5), pages 995-1026, September.
- Daniel McFadden, 1987. "A Method of Simulated Moments for Estimation of Discrete Response Models Without Numerical Integration," Working papers 464, Massachusetts Institute of Technology (MIT), Department of Economics.
- Berry, Steven & Levinsohn, James & Pakes, Ariel, 1995. "Automobile Prices in Market Equilibrium," Econometrica, Econometric Society, vol. 63(4), pages 841-90, July.
- Stigler, George J & Becker, Gary S, 1977. "De Gustibus Non Est Disputandum," American Economic Review, American Economic Association, vol. 67(2), pages 76-90, March.
- Paul R. Milgrom & John Roberts, 1984.
"Price and Advertising Signals of Product Quality,"
Cowles Foundation Discussion Papers
709, Cowles Foundation for Research in Economics, Yale University.
- Fiona M. Scott Morton, 1997. "Entry Decisions in the Generic Pharmaceutical Industry," NBER Working Papers 6190, National Bureau of Economic Research, Inc.
- Pakes, Ariel & Pollard, David, 1989. "Simulation and the Asymptotics of Optimization Estimators," Econometrica, Econometric Society, vol. 57(5), pages 1027-57, September.
- Matthew Shum, 1998. "Characterizing Informational Barriers To Entry In The Anti-Ulcer Drug Market," Working Papers mshum-98-03, University of Toronto, Department of Economics.
- Tülin Erdem & Michael P. Keane, 1996. "Decision-Making Under Uncertainty: Capturing Dynamic Brand Choice Processes in Turbulent Consumer Goods Markets," Marketing Science, INFORMS, vol. 15(1), pages 1-20.
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