The folly of making political prediction markets like Intrade illegal

The precision that makes them so theoretically useful is itself a curse for their liquidity, so prediction market evangelists should welcome all new traders with open arms.

Oftentimes with surprisingly little liquidity, prediction markets prove highly accurate and robust in the face of interference. The "wisdom of crowds" phenomenon ensures that these markets frequently outperform traditional forecasting tools like polls. For instance, the University of Iowa operates the Iowa Electronic Markets (IEM) as a research pro... See more

Prediction markets work because traders can see all of the standard forecast data and aggregate it along with other idiosyncratic or dispersed information about the election. Traders can aggregate polling data or follow published poll aggregates, and they can add in any other information they think is relevant.