The Politimetrics provides implied probabilities of Clinton or Obama winning in November if they get the nomination, derived from Intrade prices. I’m surprised that it’s been showing recently that the difference in their electabilities has been mostly zero, with occasional indications that Clinton is slightly more electable. Most other sources of information appear to suggest that Obama has more support than Clinton among independents and Republicans.
I just did a little trading to help move the market toward showing Obama as more electable by replacing my small bet against Clinton being nominated with a bet against her becoming president, but the amount I’m willing to trade was small enough that the markets moved in the opposite direction (i.e. showed increased Clinton electability).
What could cause the markets to indicate knowledge that conflicts with what I expect?
It could be that several limitations of Intrade impair market efficiency, such as not making it easy to see what those of us who have noticed the Politimetrics site see, or having margin requirements that are not conducive to exploiting inefficiencies of this nature (even if I were more confident that the market is wrong, the expected return on investment isn’t enough to persuade me to make large trades).
It could be that Obama is sufficiently unusual that there’s more uncertainty in how he will do, so that while the most likely result is that he’d get more votes than Clinton would, there’s a greater chance of a negative surprise with him.
It could be that Clinton is expected to be sufficiently vicious if she’s losing that she would hurt Obama before giving up.
But the history shown on the Politimetrics site has swings that seem unexplained by these guesses.