There is a veritable orgy of polling out today, so let's give you the numbers first, and then take a gaze from 30,000 feet.
There
are certainly some hints that Barack Obama has gained back a couple of
points' worth of ground in the past 24-96 hours, although so far this
remains more apparent in the national trackers than in state polling.
Our model is designed to react somewhat conservatively to new
information, lest it mistake noise for signal. I know that a lot of
Democrats out there -- including myself, frankly -- believe that the
movement is real, as the country reacts to the Wall Street crisis and
other news from the campaign trail. But there have been other points --
such as following Obama's Berlin speech -- in which the polls changed
sharply for a couple of days and then settled back down.
One of the disadvantages of the method we use to model our trendline curve (LOESS regression) is that there is no a priori
answer as to just how sensitive the curve should be in terms of
reacting to new information. My attempts to come up with an empirical
answer were mostly fruitless, although there is some evidence that the
curve should become more sensitive as we get closer to the election. A
week or so ago, as the model was slow to recognize the McCain bounce; I
tuned the sensitivity up slightly then, and I tuned it up very slightly
again today. I will also make the curve quite sensitive in the week or
so before the election, such that we can adequately capture any late
movement. But for the time being, Obama is either going to have to
sustain his relatively strong tracking poll results for a couple more
days, or get some slightly more consistent results from the state
polling, before we are again ready to call the race a tie or an Obama
lead.
The other thing that's happening is that, even as the
popular vote gap has narrowed, the gap between the popular vote and the
Electoral College -- which had been working to Obama's benefit -- has
also diminished. We now show about a 7 percent chance that Obama would
win the Electoral College while losing the popular vote; a couple of
days ago, that figure had been as high as 12 percent. This is mostly
because the state-by-state polling has been frankly very difficult to
interpret in the post-convention period. There are four key states in
which Obama is hoping to play offense: Colorado, Virginia, Ohio and
Florida. Winning any one of those states will probably win him the
election. But in each of these states he has had a mix of good and bad
polling. In Colorado in particular, which is probably the most
favorable to him of these states, the two polls out this week (ARG and
Rasmussen) have shown him slightly behind.
***
Much of today's polling is from American Research Group, which has numbers out in 25 states and the District of Columbia. ARG, as regular readers of this site should know, is not the most terrific pollster,
but with that said most of these results look pretty reasonable. The
results that have caught people's attention are McCain's relatively
strong performance in Illinois and Obama's relatively strong
performance in Montana and West Virginia. Some of these -- particularly
the Illinois number -- are probably outliers (ARG also had some very
weird results in Illinois during the Democratic primaries). But if a
pollster puts out 20 or 30 polls, mathematically outliers are bound to
happen in at least a couple of states. Fortunately, our model has
numerous ways to hedge against the results of outlier polls, and so
this isn't something you should spend a great deal of time worrying
about.
CNN/Time also has some very favorable looking
results for Obama, particularly in Florida and Ohio, where he leads by
4 and 2 points respectively with third-party candidates included. (This
is the version of the polls that we prefer; other outlets will use the
version without third-party candidates). These CNN polls are very
recent, so it's possible that they're detecting some kind of very
recent shift toward Obama. On the other hand, our model also identifies
the CNN/Time polls as having as having a Democratic lean of a point or
two, and hedges slightly against these numbers as a result.
--Nate Silver