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Market Experimentation in a Dynamic Differentiated-Goods Duopoly

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  • Godfrey Keller
  • Sven Rady

Abstract

We study the evolution of prices in a symmetric duopoly where firms are uncertain about the degree of product differentiation. Customers sometimes perceive the products as close substitutes, sometimes as highly differentiated. Firms learn about their competitive environment from the quantities sold and a background signal. As the information of the market outcomes increases with the price differential, there is scope for active learning. In a setting with linear demand curves, we derive firms' pricing strategies as payoff-symmetric mixed or correlated Markov perfect equilibria of a stochastic differential game where the common posterior belief is the natural state variable. When information has low value, firms charge the same price as would be set by myopic players, and there is no price dispersion. When firms value information more highly, on the other hand, they actively learn by creating price dispersion. This market experimentation is transient, and most likely to be observed when the firms' environment changes sufficiently often, but not too frequently.

Suggested Citation

  • Godfrey Keller & Sven Rady, 1999. "Market Experimentation in a Dynamic Differentiated-Goods Duopoly," STICERD - Theoretical Economics Paper Series 369, Suntory and Toyota International Centres for Economics and Related Disciplines, LSE.
  • Handle: RePEc:cep:stitep:369
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    File URL: http://sticerd.lse.ac.uk/dps/te/te369.pdf
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    References listed on IDEAS

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    Citations

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    Cited by:

    1. Heski Bar-Isaac, 2001. "Self-Confidence and Survival," FMG Discussion Papers dp395, Financial Markets Group.
    2. Bergemann, Dirk & Valimaki, Juuso, 2002. "Entry and Vertical Differentiation," Journal of Economic Theory, Elsevier, vol. 106(1), pages 91-125, September.
    3. Dirk Bergemann & Juuso Valimaki, 1999. "Entry and Innovation in Vertically Differentiated Markets," Discussion Papers 1260, Northwestern University, Center for Mathematical Studies in Economics and Management Science.

    More about this item

    Keywords

    Duopoly experimentation; Bayesian learning; stochastic differential game; Markov-perfect equilibrium; mixed strategies; correlated equilibrium.;

    JEL classification:

    • C73 - Mathematical and Quantitative Methods - - Game Theory and Bargaining Theory - - - Stochastic and Dynamic Games; Evolutionary Games
    • D43 - Microeconomics - - Market Structure, Pricing, and Design - - - Oligopoly and Other Forms of Market Imperfection
    • D83 - Microeconomics - - Information, Knowledge, and Uncertainty - - - Search; Learning; Information and Knowledge; Communication; Belief; Unawareness

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