The thrill of prediction markets for political junkies is that they harness “the wisdom of crowds.” A single person’s bet on an election outcome isn’t very good, but thousands of bets, with real stakes, are more likely to predict the correct result than even the best pundit. The Iowa Electronic Markets, the big daddy of the political prediction markets, is consistently better at forecasting winners than pre-election polls. (Read a 2003 Slate “Explainer” about prediction markets here.)
If a single prediction market is wiser than the pundits and the polls, imagine how wise all the prediction markets are together. That’s the idea behind Slate’s “Political Futures,” which offers a comprehensive guide to all the big political prediction markets. From now until Election Day 2008, we’ll publish regular updates of the key data from Iowa Electronic Markets, Intrade.com, Newsfutures.com, and Casualobserver.net. (Casualobserver has not yet launched its 2008 political prediction market, but we will add it as soon as it goes up.) In these early days of the campaign, we are tracking four markets: 1) Democratic nominee for president, 2) Republican nominee for president, 3) presidential victor, and 4) party control of the presidency. We’ll add Senate and House races as they heat up next year.
I hesitate to say that this is a sign of prediction markets breaking into the mainstream. I don’t actually see prediction markets doing that anytime soon (or perhaps ever), but it is very cool and interesting to see them being incorporated into a mainstream news site. Their inclusion does show the continuing shift of media companies towards listening to their readers.