IEM Noted As Oldest, Best-Known

When you gather the opinions of the many, the consensus usually trumps the opinions of the few -- even renowned experts. That's the hypothesis behind the Efficient Market Theory, which holds that few people can consistently beat the market over time because prices already reflect investors' collective beliefs -- the basis of the hugely successful index-fund business. No wonder many smart people think "prediction markets" will spread through business, finance and, eventually, government. Perhaps the oldest and best-known example of a prediction market is the IOWA ELECTRONIC MARKETS at the University of Iowa, which has prognosticated presidential elections -- better than the polls -- since 1988.