And it underscores for me that conditional prediction markets should almost never be taken seriously, and indicates that only the most liquid markets in general should ever be cited.
This conclusion seems too strong. For almost all of those options the probability of resolving N/A was very high, so the incentive to correct the price was low. That’s not true of many conditional markets, like “If Republicans/Democrats win the presidency, will border crossings be above [number]”, and then the probability of resolving N/A is more like 50% and the incentive to correct prices remains. Does that really justify “almost never” taking conditional markets seriously? Same for “only the most liquid markets” “should ever be cited”—the market I think you said that people had forgotten about only had about 22 traders when it was at 60%, which isn’t a lot. I don’t see why this means markets that aren’t the most liquid but have 500 traders, or markets on polymarket that have ten thousand $ in volume (small for polymarket) should not ever be cited. Manifold markets do have problems with accuracy but it’s not that bad.
So the sharps would have no reason to get involved if even one of the contenders has numbers that are off by a couple points from a sane prior.
Yes 50% chance of N/A would add a ‘couple points’ of noise, but that doesn’t make the market useless if it shows a larger difference. In the market you took a screenshot of Shapiro appears to have been at a reasonable 46% for most of the market’s existence.
This conclusion seems too strong. For almost all of those options the probability of resolving N/A was very high, so the incentive to correct the price was low. That’s not true of many conditional markets, like “If Republicans/Democrats win the presidency, will border crossings be above [number]”, and then the probability of resolving N/A is more like 50% and the incentive to correct prices remains. Does that really justify “almost never” taking conditional markets seriously? Same for “only the most liquid markets” “should ever be cited”—the market I think you said that people had forgotten about only had about 22 traders when it was at 60%, which isn’t a lot. I don’t see why this means markets that aren’t the most liquid but have 500 traders, or markets on polymarket that have ten thousand $ in volume (small for polymarket) should not ever be cited. Manifold markets do have problems with accuracy but it’s not that bad.
Yes 50% chance of N/A would add a ‘couple points’ of noise, but that doesn’t make the market useless if it shows a larger difference. In the market you took a screenshot of Shapiro appears to have been at a reasonable 46% for most of the market’s existence.