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Estimating Firm-Level Demand at a Price Comparison Site: Accounting for Shoppers and the Number of Competitors

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  • Baye, Michael
  • GATTI, RUPERT J
  • Kattuman, Paul
  • Morgan, John

Abstract

Clearinghouse models of online pricing---such as Varian (1980), Rosenthal (1980), Narasimhan (1988), and Baye-Morgan (2001)---view a price comparison site as an "information clearinghouse" where shoppers and loyals obtain price and product information to make online purchases. These models predict that the responsiveness of a firm's demand to a change in its price depends on the number of sellers and whether the price change results in the firm charging the lowest price in the market. Using a unique firm-level dataset from Kelkoo.com (Yahoo!'s European price comparison site), we examine these predictions by providing estimates of the demand for PDAs. Our results indicate that the number of competing sellers and both the firm's location on the screen and relative ranking in the list of prices are important determinants of an online retailer's demand. We find that an online monopolist faces an elasticity of demand of about -2, while sellers competing against 10 other sellers face an elasticity of about -6. We also find empirical evidence of a discontinuous jump in a firm's demand as its price declines from the second-lowest to the lowest price. Our estimates suggest that about 13% of the consumers at Kelkoo are "shoppers" who purchase from the seller offering the lowest price.

Suggested Citation

  • Baye, Michael & GATTI, RUPERT J & Kattuman, Paul & Morgan, John, 2004. "Estimating Firm-Level Demand at a Price Comparison Site: Accounting for Shoppers and the Number of Competitors," Competition Policy Center, Working Paper Series qt923692d1, Competition Policy Center, Institute for Business and Economic Research, UC Berkeley.
  • Handle: RePEc:cdl:compol:qt923692d1
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    References listed on IDEAS

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    1. Michael R. Baye & John Morgan & Patrick Scholten, 2004. "Price Dispersion In The Small And In The Large: Evidence From An Internet Price Comparison Site," Journal of Industrial Economics, Wiley Blackwell, vol. 52(4), pages 463-496, December.
    2. Michael R. Baye & John Morgan & Patrick Scholten, 2004. "Temporal Price Dispersion: Evidence from an Online Consumer Electronics Market," Working Papers 2004-04, Indiana University, Kelley School of Business, Department of Business Economics and Public Policy.
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    13. Terza, Joseph V., 1998. "Estimating count data models with endogenous switching: Sample selection and endogenous treatment effects," Journal of Econometrics, Elsevier, vol. 84(1), pages 129-154, May.
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    17. Glenn Ellison & Sara Fisher Ellison, 2009. "Search, Obfuscation, and Price Elasticities on the Internet," Econometrica, Econometric Society, vol. 77(2), pages 427-452, March.
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    Citations

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    Cited by:

    1. Glenn Ellison & Sara Fisher Ellison, 2006. "Internet Retail Demand: Taxes, Geography, and Online-Offline Competition," NBER Working Papers 12242, National Bureau of Economic Research, Inc.
    2. Michael R. Baye & John Morgan, 2009. "Brand and Price Advertising in Online Markets," Management Science, INFORMS, vol. 55(7), pages 1139-1151, July.
    3. Steve Thompson, 2009. "Grey Power: An Empirical Investigation of the Impact of Parallel Imports on Market Prices," Journal of Industry, Competition and Trade, Springer, vol. 9(3), pages 219-232, September.
    4. Kosmopoulou, Georgia & De Silva, Dakshina G., 2007. "The effect of shill bidding upon prices: Experimental evidence," International Journal of Industrial Organization, Elsevier, pages 291-313.
    5. Haynes, Michelle & Thompson, Steve, 2008. "Price, price dispersion and number of sellers at a low entry cost shopbot," International Journal of Industrial Organization, Elsevier, vol. 26(2), pages 459-472, March.
    6. Häring, Julia, 2005. "The Virtual Location of E-Tailers: Evidence from a B2C E-Commerce Market," ZEW Discussion Papers 05-52, ZEW - Zentrum für Europäische Wirtschaftsforschung / Center for European Economic Research.
    7. Harriet Gamper, 2012. "How Can Internet Comparison Sites Work Optimally for Consumers?," Journal of Consumer Policy, Springer, vol. 35(3), pages 333-353, September.
    8. Michael R. Baye & John Morgan & Patrick Scholten, 2006. "Information, Search, and Price Dispersion," Working Papers 2006-11, Indiana University, Kelley School of Business, Department of Business Economics and Public Policy.

    More about this item

    Keywords

    Internet; Price Dispersion; Advertising;

    JEL classification:

    • D1 - Microeconomics - - Household Behavior
    • D2 - Microeconomics - - Production and Organizations
    • D3 - Microeconomics - - Distribution
    • D4 - Microeconomics - - Market Structure, Pricing, and Design

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