Mark Blumenthal | September 30, 2008
Topics: Status Update
We logged ten new statewide polls yesterday, including seven -- five from Fox/Rasmussen and one each from SurveyUSA and PPP -- that tracked results from last week or mid-September. All seven showed improvements of between two and five percentage points on the margin for Barack Obama. Although our state classifications remain unchanged since yesterday, our estimates have shifted slightly in Obama's direction in 4 of the 6 battleground states for which we have new surveys (Florida, Pennsylvania, North Carolina and Virginia).
We did see a shift in the North Carolina Senate race, where a new PPP survey shows Democratic challenger Kay Hagan leading by eight points (46% to 38%) over Republican Senator Elizabeth Dole. That result confirms an existing upward trend for Hagan, and increases her lead to 4 points on our overall estimate (45.1% to 41.1%), enough to shift the race from toss-up to lean Hagan.
Back to the presidential race. I have noted previously in these updates that our trend estimator tends to be "small-c" conservative by design: It smooths out the line, which may sometimes understate a trend, especially if we see a significant shift nationally but only one or two new surveys in each state. We saw that lag just after the Republican convention, when it took about a week for the McCain-Palin bump to show up clearly on our map, and we have seen something similar in the Obama-Biden rebound over the last two weeks.
The "more sensitive" setting on the "smoothing" tool in our new Flash charts provides a way to check for potential short term trends. Consider Pennsylvania. Our standard trend estimate shows Barack Obama with a 3.3% lead (48.0% to 44.7% at the time of this posting**):
However, the more sensitive estimate, which gives greater weight to the more recent surveys in Pennsylvania that show Barack Obama running "above trend," gives the Democrat a lead of just over seven points (49.9% to 42.8%). That margin would be more than enough to shift Pennsylvania back to the "lean Obama" category:
The "more sensitive" trend estimate setting comes with an important warning: It is more apt to be "fooled" by outliers or other random noise in the data, so some of the short terms shifts it plots may turn out to be illusory.
To try to check for that possibility, I ran the more sensitive estimates -- again, as of this writing -- for the 12 of the 14 battleground states I have been monitoring for these updates (we lack sufficient polls to calculate a more sensitive trend in West Virginia and Indiana). As the table below shows, Obama does better on the more sensitive trend estimate in 9 of 12 states.
The bottom line: The national trackers are showing additional gains for Obama over the last week. These gains are probably not yet fully registered on the standard state trend estimates that drive our map. If these gains hold -- a big "if" -- we will likely see continuing movement to Obama on the national map over the next week.
PS: Charles Franklin is traveling today and has not had a chance to run and send the "national forces" charts. I will update when he does.
**The numbers in the text match the chart as of 7:00 a.m. Eastern Time. Any polls added after that will change the estimates.