Fraud detection in play-money prediction markets
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Prediction markets are increasingly used to aggregate information on particular future events of interest such as elections, sports events, and Oscar winners. However, prediction markets are sensitive to manipulation and price distortions. In this paper, we show evidence for fraud in a play-money sports prediction market. In contrast to the often considered outcome manipulation in the context of political stock markets we were only looking for violations of our general terms and conditions, i.e., for traders creating multiple user accounts and trading against themselves in order to transfer cash from one account to another. We found evidence of suchlike coalitions and received complaints about it by annoyed traders. We discuss possible countermeasures in order to avoid or at least detect this kind of fraud in play-money prediction markets and present a tool which can be used to detect coalition building while operating a market.
KeywordsPrediction markets Fraud detection Manipulation Coalition building
This work is based on research funded by the German Federal Ministry for Education and Research under grant number 01HQ0522 and by the German Research Foundation (DFG) within the scope of the Graduate School Information Management and Market Engineering (IME). The authors are responsible for the content of this publication.
- Berg JE, Forsythe R, Nelson F, Rietz TA (2001) Results from a Dozen years of election futures markets research. In: Plott CR, Smith VL (eds) Handbook of experimental economic results. Elsevier Press, New YorkGoogle Scholar
- Garey MR, Johnson DS (1979) Computers and intractability: a guide to the theory of NP-completeness. (W.H.) Freeman, New YorkGoogle Scholar
- Gini C (1936) On the measure of concentration with special reference to income and wealth. Abstracts of papers presented at the Cowels Commission Research Conference on Economics and Statistics. Colorado Springs, Colorado College, pp 73–80Google Scholar
- Hanson R, Oprea R (2004) Manipulators increase information market accuracy. George Mason University Working PaperGoogle Scholar
- Luckner S, Weinhardt C (2007) How to pay trader in information markets? Results from a field experiment. J Prediction Mark 1(2):147–156Google Scholar
- Oprea R, Porter D, Hibert C, Hanson R, Tila D (2006) Can manipulators mislead prediction market observers? George Mason University Working PaperGoogle Scholar
- Rolli D, Neumann D, Weinhardt C (2004) A minimal market model in ephemeral markets. In: Proceedings of the form EMC, Toledo, SpainGoogle Scholar
- Slamka C, Luckner S, Seemann T, Schroeder J (2008) An empirical investigation of the forecast accuracy of play-money prediction markets and professional betting markets. In: Proceeding of the 16th European Conference on Information Systems (ECIS), Galway, IrelandGoogle Scholar
- Wolfers J, Zitzewitz E (2006) Five open questions about prediction markets. In: Tetlock P, Hahn RW (eds) Information markets: a new way of making decisions. AEI-Brookings Joint Center for Regulatory Studies, pp 13–39Google Scholar