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Adverse selection and moral hazard in anonymous markets


  • Klein, Tobias J.
  • Lambertz, Christian
  • Stahl, Konrad O.


We study the effects of improvements in eBay's rating mechanism on seller exit and continuing sellers' behavior. Following a large sample of sellers over time, we exploit the fact that the rating mechanism was changed to reduce strategic bias in buyer rating. That improvement did not lead to increased exit of poorly rated sellers. Yet, buyer valuation of the staying sellers-especially the poorly rated ones-improved significantly. By our preferred interpretation, the latter effect results from increased seller effort; also, when sellers have the choice between exiting (a reduction in adverse selection) and improved behavior (a reduction in moral hazard), then they prefer the latter because of lower cost.

Suggested Citation

  • Klein, Tobias J. & Lambertz, Christian & Stahl, Konrad O., 2013. "Adverse selection and moral hazard in anonymous markets," ZEW Discussion Papers 13-050, ZEW - Zentrum für Europäische Wirtschaftsforschung / Center for European Economic Research.
  • Handle: RePEc:zbw:zewdip:13050

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    References listed on IDEAS

    1. Patrick Bajari & Han Hong & Ahmed Khwaja, 2006. "Moral Hazard, Adverse Selection and Health Expenditures: A Semiparametric Analysis," NBER Working Papers 12445, National Bureau of Economic Research, Inc.
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    3. Amy Finkelstein & James Poterba, 2004. "Adverse Selection in Insurance Markets: Policyholder Evidence from the U.K. Annuity Market," Journal of Political Economy, University of Chicago Press, vol. 112(1), pages 183-208, February.
    4. Paul Resnick & Richard Zeckhauser & John Swanson & Kate Lockwood, 2006. "The value of reputation on eBay: A controlled experiment," Experimental Economics, Springer;Economic Science Association, vol. 9(2), pages 79-101, June.
    5. Klein, Tobias J. & Lambertz, Christian & Spagnolo, Giancarlo & Stahl, Konrad O., 2006. "Last Minute Feedback," Discussion Paper Series of SFB/TR 15 Governance and the Efficiency of Economic Systems 62, Free University of Berlin, Humboldt University of Berlin, University of Bonn, University of Mannheim, University of Munich.
    6. Aviva Aron-Dine & Liran Einav & Amy Finkelstein & Mark Cullen, 2012. "Moral hazard in health insurance: How important is forward looking behavior?," Discussion Papers 11-007, Stanford Institute for Economic Policy Research.
    7. Jaap H. Abbring & James J. Heckman & Pierre-André Chiappori & Jean Pinquet, 2003. "Adverse Selection and Moral Hazard In Insurance: Can Dynamic Data Help to Distinguish?," Journal of the European Economic Association, MIT Press, vol. 1(2-3), pages 512-521, 04/05.
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    11. David Dranove & Ginger Zhe Jin, 2010. "Quality Disclosure and Certification: Theory and Practice," Journal of Economic Literature, American Economic Association, vol. 48(4), pages 935-963, December.
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    13. Melnik, Mikhail I & Alm, James, 2002. "Does a Seller's Ecommerce Reputation Matter? Evidence from eBay Auctions," Journal of Industrial Economics, Wiley Blackwell, vol. 50(3), pages 337-349, September.
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    Cited by:

    1. Jolivet, Grégory & Jullien, Bruno & Postel-Vinay, Fabien, 2016. "Reputation and prices on the e-market: Evidence from a major French platform," International Journal of Industrial Organization, Elsevier, vol. 45(C), pages 59-75.
    2. Chris Nosko & Steven Tadelis, 2015. "The Limits of Reputation in Platform Markets: An Empirical Analysis and Field Experiment," NBER Working Papers 20830, National Bureau of Economic Research, Inc.

    More about this item


    Anonymous markets; adverse selection; moral hazard; reputation building mechanisms;

    JEL classification:

    • D83 - Microeconomics - - Information, Knowledge, and Uncertainty - - - Search; Learning; Information and Knowledge; Communication; Belief; Unawareness
    • L15 - Industrial Organization - - Market Structure, Firm Strategy, and Market Performance - - - Information and Product Quality

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