@TECHREPORT\{IMM2000-05365, author = "D. M. Pennock and S. Lawrence and C. L. Giles and F. {\AA}. Nielsen", title = "The Power of Play: Efficiency and Forecast Accuracy in Web Market Games", year = "2000", keywords = "artificial markets", number = "", series = "{NEC} Research Institute Technical Report", institution = "{NEC} Research Institute", address = "Princeton, New Jersey", type = "", note = "A brief version appears in Science 291: 987-988, February {9,} 2001.", url = "http://artificialmarkets.com/", abstract = "We analyze the efficiency and forecast accuracy of two market games on the World Wide Web: the Hollywood Stock Exchange (HSX) and the Foresight Exchange (FX). We quantify the degree of arbitrage available on {HSX,} and compare with a real-money market of a similar nature. We show that prices of {HSX} movie stocks provide good forecasts of actual box office returns, and that prices of {HSX} securities in Oscar, Emmy, and Grammy award outcomes constitute accurate assessments of the actual likelihoods that nominees will win. Similar investigations reveal that {FX} securities prices serve as reliable indicators of uncertain future events. We argue that, in certain circumstances, market simulations can furnish some of the same societal benefits as real markets, and can serve as acceptable substitute testbeds for conducting experiments that would otherwise be difficult or impossible.", isbn_issn = "2000-168" }