This file is part of IDEAS, which uses RePEc data


[ Papers | Articles | Software | Books | Chapters | Authors | Institutions | JEL Classification | NEP reports | Search | New papers by email | Author registration | Rankings | Volunteers | FAQ | Blog | Help! ]

Inference by Believers in the Law of Small Numbers

Author info | Abstract | Publisher info | Download info | Related research | Statistics
Author Info
Matthew Rabin.
Abstract

JEL#: B49
Keywords: Bayesian Inference, the gambler' fallacy, law of large numbers, law of small numbers, over-inference
Many people believe in the "Law of Small Numbers," exaggerating the degree to which a small sample resembles the population from which it is drawn. To model this, I assume that a person exaggerates the likelihood that a short sequence of i.i.d. signals resembles the long-run rate at which those signals are generated. Such a person believes in the "gambler's fallacy", thinking early draws of one signal increase the odds of next drawing other signals. When uncertain about the rate, the person over-infers from short sequences of signals, and is prone to think the rate is more extreme than it is. When the person makes inferences about the frequency at which rates are generated by different sources -- such as the distribution of talent among financial analysts -- based on few observations from each source, he tends to exaggerate how much variance there is in the rates. Hence, the model predicts that people may pay for financial advice from "experts" whose expertise is entirely illusory. Other economic applications are discussed.
June 2000

Download Info
To download:

If you experience problems downloading a file, check if you have the proper application to view it first. Information about this may be contained in the File-Format links below. In case of further problems read the IDEAS help page. Note that these files are not on the IDEAS site. Please be patient as the files may be large.

File URL: http://www.haas.berkeley.edu/groups/iber/wps/econ/E00-282.pdf
Our checks indicate that this address may not be valid because: 404 Not Found (http://www.haas.berkeley.edu/groups/iber/wps/econ/E00-282.pdf [302 Found]--> http://iber.berkeley.edu/wps/econ/E00-282.pdf). If this is indeed the case, please notify (Christopher F. Baum)
File Format: application/pdf
File Function: main text
Download Restriction: no

Publisher Info
Paper provided by University of California at Berkeley in its series Economics Working Papers with number E00-282.

Download reference. The following formats are available: HTML (with abstract), plain text (with abstract), BibTeX, RIS (EndNote, RefMan, ProCite), ReDIF
Length:
Date of creation: 01 Jun 2000
Date of revision:
Handle: RePEc:ucb:calbwp:e00-282

Contact details of provider:
Postal: University of California at Berkeley, Berkeley, CA USA
Phone: 510-642-0822
Fax: 510-642-6615
Email:
Web page: http://www.haas.berkeley.edu/groups/iber/wps/econwp.html
More information through EDIRC

Order Information:
Postal: IBER, F502 Haas Building, University of California, Berkeley CA 94720-1922
Email:

For technical questions regarding this item, or to correct its listing, contact: (Christopher F. Baum).

Related research
Keywords:

This paper has been announced in the following NEP Reports:

References listed on IDEAS
Please report citation or reference errors to , or , if you are the registered author of the cited work, log in to your RePEc Author Service profile, click on "citations" and make appropriate adjustments.:
  1. Harrison Hong & Terence Lim & Jeremy C. Stein, 1998. "Bad News Travels Slowly: Size, Analyst Coverage and the Profitability of Momentum Strategies," NBER Working Papers 6553, National Bureau of Economic Research, Inc. [Downloadable!] (restricted)
  2. Matthew Rabin, 1998. "Psychology and Economics," Journal of Economic Literature, American Economic Association, vol. 36(1), pages 11-46, March. [Downloadable!] (restricted)
  3. Joel L. Schrag, 1999. "First Impressions Matter: A Model Of Confirmatory Bias," The Quarterly Journal of Economics, MIT Press, vol. 114(1), pages 37-82, February. [Downloadable!] (restricted)
  4. Keren, Gideon & Lewis, Charles, 1994. "The Two Fallacies of Gamblers: Type I and Type II," Organizational Behavior and Human Decision Processes, Elsevier, vol. 60(1), pages 75-89, October. [Downloadable!] (restricted)
  5. Camerer, Colin F, 1989. "Does the Basketball Market Believe in the 'Hot Hand'?," American Economic Review, American Economic Association, vol. 79(5), pages 1257-61, December. [Downloadable!] (restricted)
  6. Sendhil Mullainathan, 2002. "A Memory-Based Model Of Bounded Rationality," The Quarterly Journal of Economics, MIT Press, vol. 117(3), pages 735-774, August. [Downloadable!] (restricted)
  7. Kent Daniel & David Hirshleifer & Avanidhar Subrahmanyam, 1998. "Investor Psychology and Security Market Under- and Overreactions," Journal of Finance, American Finance Association, vol. 53(6), pages 1839-1885, December. [Downloadable!] (restricted)
  8. Grether, David M, 1980. "Bayes Rule as a Descriptive Model: The Representativeness Heuristic," The Quarterly Journal of Economics, MIT Press, vol. 95(3), pages 537-57, November. [Downloadable!] (restricted)
  9. Jonathan B. Berk & Richard C. Green & Vasant Naik, 1999. "Optimal Investment, Growth Options, and Security Returns," Journal of Finance, American Finance Association, vol. 54(5), pages 1553-1607, October. [Downloadable!] (restricted)
  10. De Bondt, Werner F M & Thaler, Richard H, 1990. "Do Security Analysts Overreact?," American Economic Review, American Economic Association, vol. 80(2), pages 52-57, May. [Downloadable!] (restricted)
  11. De Bondt, Werner F M & Thaler, Richard H, 1987. " Further Evidence on Investor Overreaction and Stock Market Seasonalit y," Journal of Finance, American Finance Association, vol. 42(3), pages 557-81, July. [Downloadable!] (restricted)
  12. Mark Walker & John Wooders, 2001. "Minimax Play at Wimbledon," American Economic Review, American Economic Association, vol. 91(5), pages 1521-1538, December. [Downloadable!] (restricted)
  13. Charles T. Clotfelter & Philip J. Cook, 1991. "The "Gambler's Fallacy" in Lottery Play," NBER Working Papers 3769, National Bureau of Economic Research, Inc. [Downloadable!] (restricted)
  14. Nicholas Barberis & Ming Huang & Tano Santos, 1999. "Prospect Theory and Asset Prices," NBER Working Papers 7220, National Bureau of Economic Research, Inc. [Downloadable!] (restricted)
Full references

Cited by:
(explanations, Please report citation or reference errors to , or , if you are the registered author of the cited work, log in to your RePEc Author Service profile, click on "citations" and make appropriate adjustments.)

  1. Temple, Jonathan, 2001. "Growing into Trouble: Indonesia After 1966," CEPR Discussion Papers 2932, C.E.P.R. Discussion Papers. [Downloadable!] (restricted)
Statistics
Access and download statistics

Did you know? Over five million full texts a year are downloaded through IDEAS.

This page was last updated on 2009-11-27.

This information is provided to you by IDEAS at the Department of Economics, College of Liberal Arts and Sciences, University of Connecticut using RePEc data on a server sponsored by the Society for Economic Dynamics.