Tradesports Senate numbers

[Mr. Morden]

I've noticed just within the last day or two that, in most of the races where one candidate had been leading but it had been kind of close, the favored candidate has now started pulling away.  Menendez in NJ, Tester in MT, Whitehouse in RI, even Corker in TN has started to build up a bit of a lead.  I'm assuming that, with just one week left, people are coming to the conclusion that there isn't enough time left for the trailing candidate to rebound.  OTOH, you have MO (which is now, and has pretty much always been, a near tie) and VA (which has now moved into a near tie, based on the recent polling).  The only other race that seems to be tightening is MD, which still isn't as close as MO, VA, or TN, but which does seem to show a little momentum for Steele on Tradesports.

[Mr. Morden]

On a related note, the Tradesports odds for the GOP retaining the House are now at an all time low of 25.1%.  As with the Senate, I wouldn't attribute this to any big movement in the polls....just to the fact that the GOP is down, and time is running out for them to change things.  Still, the way many prognosticators are talking, you'd think the odds of the GOP holding the House were significantly *lower* than 25%.

[Mr. Morden]

The Tradesports odds on GOP retention of the House is now in complete freefall.  It's now at an all time low of 18%, whereas it was about double that just a week ago.  Again, I think this is because people had been thinking that the GOP still had time to turn this around, but now it's too late.  With only three days left, there just isn't enough time for the GOP to make a comeback.

[Mr. Morden]

No, the probabilities aren't independent.

Exactly.  You can only multiply the probabilities together if the events are completely independent of one another.  But almost every election sees a minor shift towards one party or the other from the pre-election polls to the actual result.  So there's a decent chance that all of the closest races will go the same way.....at least, a better chance than you'd get just by multiplying the probabilities.

[Mr. Morden]

Just today, for (I think) the first time on Tradesports, Webb is now rated as having a better chance of winning than Tester.  That is, both MT and VA are still listed as slight advantage-Dem, but MT is now rated as being closer than VA.

[Mr. Morden]

The problem is that the Democrats need all 5 of those marginal seats. Those probabilities are somewhat independent of each other (of course they're also somewhat correlated).

Also, as time goes on, the probabilities become more independent, since the less time there is left, the lower the chances of some big event swinging all of the seats in the same direction.  The more independent the races become, the harder it is for either party to win all of them.