CNN’s early exit polls have been leaked to ThinkProgress (assuming they’re not lying to us, that is). If they’re accurate, the Dems have won the House, and may have won the Senate. Tradesports now (6.20pm US EST) have the GOP an 11% chance to keep the House, and a 68% chance to keep the Senate.
[...] So far things look good for the Democrats. Leaked exit polls, for what they’re worth, show leads in most key races, and the early counting has confirmed some gains in the House, Senate and state governorships. [...]
Democrats on 49 Senate seats, Webb leading by 7000, Tester leading by 7000.
How’s your ‘betting markets are always right’ proposition looking, Mr Leigh?
Senate to the dems by the slimmest of margins, Tester to defeat Burns in Montana by possibly less than a 1000 votes as the GOP slowly pulls back his early lead. Mind you we won’t know for certain until after all the court cases, recounts et al. Whatever the result winning 2/3 of the Senate Seats is a considerable achivement.
Betting markets aren’t always right. On average, they’re better than the polls. Which isn’t hard, since polls are so inaccurate.
Wait and see. It’s not over yet.
http://www.marginalrevolution.com/marginalrevolution/2006/11/for_the_curious.html
What’s interesting is that the odds in the individual senate races were (the last time I checked, which was as the exit polls started leaking) correctly predicting the outcomes of those races, but with implied probabilities such that, if you added them all up, the implied probability of the Dems winning all of the races they needed to take the Senate was more like the probability implied by the senate control number.
So, I don’t think this was a complete discrediting of the predictive power of betting markets.
Though it was a welcome return to form for the exit polls!
from where I am standing the polls picked this pretty well for over a year in terms of the overall vote whilst my admittedly brief look the betting markets were all over the place.
the revenge of the t statistics!!
Given this result and the Austrian election (6 to 1 against the surprise winner) I think the evidence suggests that the betting markets make reasonable use of public information, including polls, but don’t do any better than an intelligent pundit with access to the polls and no wishful thinking.
John, I didn’t see any surveys of pundits for the US election. Let me know if you’re aware of one.
I do know of such evidence for the Australian 2004 election. A survey of ten “experts” published in the Sunday Telegraph the Sunday before polling day found that three thought Latham would win, while seven thought Howard would win, but with a smaller majority than in 2001. None forecast the true result – a Howard victory with an increased majority. By contrast, the betting odds had Howard a higher chance to win in 2004 than in 2001: suggestive evidence that the betting markets expected him to increase his majority.
Peter Brent forecast the true result…
PS – And Mr Quiggin did say an ‘intelligent’ pundit…