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Bias and Size Effects of Price-Comparison Search Engines: Theory and Experimental Evidence


  • Aurora García-Gallego

    () (Universitat Jaume I)

  • Nikolaos Georgantzís

    () (Universitat Jaume I)

  • Pedro Pereira

    () (Autoridade da Concorrência)

  • José C. Pernías-Cerrillo

    () (Universitat Jaume I)


This article, analyzes the impact on consumer prices of the size and bias of price comparison search engines. we develop a model, related to Burdett and Judd (1983) and Varian (1980), and test experimentally several theoretical predictions. The experimental results confirm the model’s predictions regarding the impact of the number of firms, and the type of bias of the search engine, but reject the model’s predictions regarding changes in the size of the index.

Suggested Citation

  • Aurora García-Gallego & Nikolaos Georgantzís & Pedro Pereira & José C. Pernías-Cerrillo, 2007. "Bias and Size Effects of Price-Comparison Search Engines: Theory and Experimental Evidence," Working Papers 20, Portuguese Competition Authority.
  • Handle: RePEc:pca:wpaper:20

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    References listed on IDEAS

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    5. Bolton, Patrick & Scharfstein, David S, 1990. "A Theory of Predation Based on Agency Problems in Financial Contracting," American Economic Review, American Economic Association, vol. 80(1), pages 93-106, March.
    6. Kyle Bagwell & Garey Ramey, 1996. "Capacity, Entry, and Forward Induction," RAND Journal of Economics, The RAND Corporation, vol. 27(4), pages 660-680, Winter.
    7. Guillermo Caruana & Liran Einav, 2008. "A Theory of Endogenous Commitment," Review of Economic Studies, Oxford University Press, vol. 75(1), pages 99-116.
    8. Daniel F. Spulber, 1989. "Regulation and Markets," MIT Press Books, The MIT Press, edition 1, volume 1, number 0262192756, January.
    9. A. Michael Spence, 1977. "Entry, Capacity, Investment and Oligopolistic Pricing," Bell Journal of Economics, The RAND Corporation, vol. 8(2), pages 534-544, Autumn.
    10. John Connor, 2001. "“Our Customers Are Our Enemies”: The Lysine Cartel of 1992–1995," Review of Industrial Organization, Springer;The Industrial Organization Society, vol. 18(1), pages 5-21, February.
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    More about this item


    Search engines; incomplete information; biased information; price levels; experiments.;

    JEL classification:

    • C91 - Mathematical and Quantitative Methods - - Design of Experiments - - - Laboratory, Individual Behavior
    • 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
    • L13 - Industrial Organization - - Market Structure, Firm Strategy, and Market Performance - - - Oligopoly and Other Imperfect Markets

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