Democrats Continue Senate Clawback; GOP Solidifies House Prospects

Democrats continued to claw their way back in the race for control of the U.S. Senate.  While there was essentially no change in the median estimate of 49.5 Senate seats in our macro model, our micro model gave Republicans their lowest estimate (47.9 seats) this month.  The reading of 47.9 represents a decline of 0.6 seats over the past two days.  The macro model's estimate of Senate control also retreated by roughly 5% from yesterday's estimate.  Both models utilize data from InTrade markets in generating their estimates. 

The Republican decline from yesterday centers primarily in a 10% decline in Washington state and an eight percent decline in Colorado in our midpoint estimates.  Republicans are above 50% in 27 of the 37 races which would yield 50 seats if Republicans prevailed in all 27.  But, as the table to the left shows, very little change is needed to tilt the field further back towards the Democrats.

As an illustration of just how volatile these markets can be at this point in time consider the table to the left from the October 18, 2006.  The percentages are the win probability percentages for Democratic candidates on an earlier version of our model.  However, the midpoint price estimate methodology varied only slightly so the comparison is relevant if not exact.

The good news for Republicans is that candidate Jim Webb had roughly the same estimated probability of defeating Senator George Allen (Virginia) as the InTrade market gives Republicans of capturing the Washington seat.  The bad news, Democrats only needed to win two of the three to seize control. They did.  Republicans on the other hand would need to run the table in comparable seats.

On the House side, Republicans continue to solidify their position.  While our midpoint seat estimate remained at 231, the probability of House control soared to 86%.  The big question for House Republicans appears to be whether they will see an increase in their seat estimates.