Prediction markets with reputation systems 

Prediction markets

For years, Robin Hanson and others have been promoting "prediction markets" and "ideas futures" as means of making various types of collective judgements under uncertainty more reliable.

The idea involves interested participants "putting their money where their mouth is" - and betting on possible outcomes.

He suggests that political policy, academic research direction, and many other fields may benefit from this approach.

However, an oft-mentioned problem with such systems is that they may allow the rich and powerful to directly influence policy - by simply throwing money at issues whose outcomes they wish to modify. Such influences might well eclipse factors which are environmental, humanist - or otherwise not economic in nature.

Reputation systems

Reputations have been used for years to allow the identification of trustworthy traders.

Participants carry their transaction history around with them - and display a summary to prospective traders.

eBay and Amazon have both employ the technique successfully.

Synergy

Combining prediction markets with reputation systems would involve placing an emphasis on the views of traders with a good track record of making successful predictions.

This would make it harder for rich organizations to influence minor decisions. As well as owning capital they would have to set up a series of traders with successful track records. In order to deliberately made influential (but inaccurate) bets they would have previously had to make a positive contribution of a string of successful predictions to the market.

As well as seeing the overall history, you could ask what previously-successful traders were saying, or what those with a successful history of transactions in the same area thought.

Traders could even be authenticated (e.g. by making sure they have their own mobile phone number) to help prevent identity duplication - further dicouraging those traders prepared to sacrifice their cash and their reputations for the chance to influence the market.

Privacy

In some markets, if you know a trader has a good track record, you can make money by shadowing their investments. However, sometimes this happens at the expense of the original investor's returns.

This might happen if you are guessing how many beans are in a jar - and the prize is split beteen those who make the correct guess.

Under such circumstances, an insightful trader would probably want to keep their portfolio or their reputation (or both) secret from other traders while bets are being taken - so they benefit more than others from their knowledge. Markets should be set up to allow for such cases.

This type of privacy issue may make it harder to extract useful information from the market - but normally that cannot be helped.

Synopsis

Reputation systems may not overcome all the flaws of prediction markets - but they could certainly help to make them more reliable and trustworthy.

Links

Futarchy: Vote Values, But Bet Beliefs

Issues In Information Market Design

Idea Futures (a.k.a. Prediction Markets, Information Markets)

Tim Tyler | Contact