CFAR (in 2012, at least) had a market where your scoring was based on how much you updated the previous bet towards the truth. I really enjoyed the interactional nature of it.
Unfortunately, this would be easy to abuse online. Create a sockpuppet account, make a stupid prediction, and then quickly fix the prediction using your real account. This is equivalent to moving bits from one account to the other.
At CFAR workshop all participants were real people. But they still missed an existing opportunity to abuse the system: there were rewards for winning, but no punishment for losing. So two people could agree to transfer a lot of bits from one to another, and split the price afterwards.
Maybe a system more difficult to abuse can be designed, but a direct copy of algorithm used at CFAR isn't it.
You're right. Gaming the system is feasible, though I believe it is very low-value.
What exactly would the point of gaming a prediction thread be? The only point-keeping would be informal, so if you're making a bunch of points off of idiotic puppets bets it's still visible as because you were up against an idiotic bet. It'd be like lying on the group diary, almost.
Do note, there was actually a HUGE punishment for losing. You could get into the negative pretty easily by being stupidly overconfident. The scoring was 100 × log2(Your probability of outcome/Pre...
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