Although the topline results don't make it obvious, it appears that
John McCain had a fairly strong night of polling in the daily tracking
polls, which are the only numbers we have to look at today.
The Gallup tracker now shows Barack Obama leading by 2 points, down from 4 a day ago. When I attempt to estimate the daily results from the topline numbers, however, I get the following:
Wednesday: Obama +7.8
Thursday: Obama +2.4
Friday: McCain +4.2
So
Obama's numbers are being propped up by a strong night of polling on
Wednesday, which will cycle out tomorrow. He also held up relatively
well on Thursday following Sarah Palin's speech (note: our estimate of
his Thursday numbers has been revised slightly upward from yesterday's
figures because of a methodological improvement I made to my tracking
poll algorithm). But yesterday, McCain had a good night, most likely
leading by somewhere in the range of 4 points. There is a good chance
that tomorrow's Gallup numbers will show a tie or a McCain lead.
As for Rasmussen ,
it actually has Barack Obama gaining a point, and moving into a 3-point
lead. However, it still looks like McCain may have had a relatively
good night on Friday. My tracking poll algorithm will have more
difficulty with the Rasmussen tracker than the Gallup tracker because
Rasmussen uses a more complicated weighting procedure (i.e. weighting
by party ID), meaning that we're a step further away from seeing "raw"
numbers. But with grain of salt, here is what I show:
Wednesday: Obama +4.9
Thursday: Obama +3.8
Friday: Obama +0.3
Once again, I would caution against overinterpreting any of this. Conventions should
produce bounces -- they are the equivalent of tens of millions of
dollars in free advertising time. What we don't know is how to
contextualize these bounces. An average convention bounce is about 6
points, but we don't know how the Democratic and Republican conventions
interact with one another, particularly as it affects the timing of the
respective bounces. Moreover, Fridays (and Saturdays) are tough nights
to poll. My hunch, as I've stated before, is that whatever numbers
McCain winds up with over the weekend, Barack Obama will probably be
polling a couple of points ahead of those numbers by the end of the
upcoming week.
--Nate Silver