[somenameforme]

But this is where stuff like prediction markets shine. In chess, for instance, the prediction market odds are going to be way closer to the outcome than might be expected because of the players' ratings. This is because skilled bettors are capable of considering things like exact matchups, history, short-term performance/form, and many other factors that a static rating can't really account for.

Incidentally this is also what makes chess games relatively profitable. Moderate-info bettors will do things like flip on their chess engine, look at the eval, and then bet on that. But a computer might say a position is a dead-draw when a stronger player can tell you 'white has big practical winning chances'.

[vintermann]

You can build a model accounting for all the things you like, you don't have to limit yourself to Elo (its main selling point is that it's easy enough that players can easily calculate how many rating points they stand to lose/gain) or Glicko (almost as easy).

Even in the most optimistic case, betting market accuracy will be limited by the commission (if you have a better estimate than the market, but not sufficiently better that you'll make money on it, you don't bet), and I think even a not-terribly-smart model can get you there for chess games. We don't need betting markets for the prediction's sake.

[somenameforme]

Polymarket not only doesn't charge a commission for market makers (the people who put out offers), but actually gives them a percent of all fees collected from market takers to help ensure and incentivize market liquidity. So if you could create a model that offered even slightly worse than market accuracy, you'd have an infinite money machine. It does not seem to exist.

And I think the reason for that is because a lot of these factors are unquantifiable, subjective, and non-fixed. For instance determining the winning chances for a human in a chess position is surprisingly complex. There's even a huge chunk of profit to be made for somebody that could create such a model outside of printing money in prediction markets - it'd be an invaluable tool for players to use during opening preparation since positions where winning chances don't correlate with computer eval are sort of the money-shot in human prep that's often motivated by a desire to avoid computer prep. And that factor is just 1 amongst many that can weigh in on an expert bettor's opinion.