Fairfax County Margin: Prediction Revised Sharply Upward

Two factors have caused me to revise my mid-September prediction. First, the final official registration totals have been tallied and while I had estimated 660,000 registrants, the actual number is slightly higher at 664,798. Second, the Obama wave in our area is apparent more than ever. Even my optimistic percentages seem conservative at this point.

My new prediction is a margin of 139,567 votes. An admittedly almost absurd margin. Let me walk through how I arrived at it.

My cautious estimate will include the adjustment to account for the slight change in the registration total and it will continue to assume the lower Kerry % among the subset that reflects the total that voted in 2004, while assuming 75% instead of 65% among new registrants. My optimistic estimate, meanwhile, will change dramatically as I bump Obama’s share up to 65% and McCain’s down to 33% reflecting the roughly 5-6% shift in this race.

Note that I haven’t changed my turnout prediction from 87% in either of my models. That’s because I think that 87% is pretty much the reasonable peak of turnout. Even as excitement grows for Obama, my pedestrian guess is that those very very weak Republican voters will drop off and not show up just as the voters on the exact other end of the spectrum are bucked up.

New Cautious Estimate
245,671 – Kerry vote
+ 90,543 – 75% of new voters
————————-
336,214 Obama votes

211,980 – Bush vote
+ 30,181 – 25% of new voters
————————-
242,161 McCain votes

New Optimistic Estimate
65% x 578,375 = 375,944 Obama votes
33% x 578,375 = 190,864 McCain votes

New Cautious Margin: 94,053
New Optimistic Margin: 185,080
Average: 139,566.5