Chart1: Daily tracking polls update, 31 October

Three days ago, I was feeling nervous about a sudden seeming lurch-let towards McCain in the daily tracking polls. This in spite of repeated posts by the experts insisting that there was no actually meaningful tightening going on, it was mostly just a question of statistical artifacts.

By this morning, Pollster.com’s status update did acknowledge that there had been some movement: “If you look at our national trend chart, we definitely show a narrower Obama margin now (5.4% as of this writing) than about a week ago.” Obama’s current national trend estimate, Mark Blumenthal explains, now stands about a point lower than his high of 50.9% a week ago, and McCain’s current estimate is slightly less than two percentage point higher than his low of 42.2% on October 12.

However, there’s still little to worry about, basically, as he points out the obvious to calm our nerves: “[T]ime is short and Obama’s lead still looks daunting. [..] Obama continues to lead on every national poll and yesterdays tracking updates show no decisive shift in either direction.”

Today’s tracking poll numbers certainly help sooth the jitters, as most actually show movement towards Obama (see Chart 1). Over the last two days, the ABC/WaPo, IBD/TIPP and Rasmussen daily trackers all have Obama’s lead back up 1 point, Zogby has it up 2, and the Gallup samples have moved back in Obama’s favour too: the regular voter and expanded likely voter samples both by 2 points and the traditional likely voter sample by no less than 5 (from 3% to 8%).

The result is that the average of all daily tracking polls has Obama’s lead back up by 1 point from +5.6% to +6.6%, after it had fallen by 2.7 points in the previous four days.

(As it happens it’s going back up in exactly symmetrical fashion; it went down from 8.3 to 7.3, 6.6, 6.0 and 5.6, and now went back up to 6.0 and 6.6. Tomorrow +7.3 again?)

Still, there’s always room for a note of caution. Gallup may have Obama leading by “his largest margin to date” in its traditional likely voter model and tying his highest advantage to date in its registered voter sample, but Rasmussen dissents. Obama’s lead in its poll has been between 3-5% for the past five days, which is “a bit tighter” than the 4-8 point margins he enjoyed for the previous month. The reason? McCain hit 47% for only the second time in over a month: “The tightening comes entirely from McCain solidifying his support.”

Chart 2: This chart plots how the average varies when you include all but one of the daily tracking polls.

Chart 2 shows how the average lead in the daily tracking polls varies if you include all but one of the daily tracking polls. What’s the effect if you ignore Zogby? How’s it look if you take TIPP out of the equation? The interesting thing is how the lines are now all almost exactly overlapping. That’s because more of a consensus appears to have emerged. Today all the tracking polls except for Gallup’s irrelevant registered voter sample have Obama’s lead in a five point range between +4 and +9. Yesterday they all had it between +4 and +8, the day before between +3 and +8.

That may still seem a pretty wide range, but it’s definitely a more solidified range than you had a week ago, or through most of the month. You can see that in the narrow brown line in Chart 2, which represents the polls’ average deviation from the mean. E.g., today the average Obama lead in the daily tracking polls is 6.6%, and each poll deviates on average 1.6 percentage points from that. On the 23rd, on the other hand, the Obama lead varied from 1% in the TIPP poll to 12% in the Zogby poll and the average deviation was 3.0 points.

A few things are still worth noting about today’s tracking polls. First, those looking at the Obama gains in the Gallup poll may be tempted to ascribe it to the impact of Obama’s 30-minute ad on the networks the other night. The Gallup write-up, however, explicitly warns against that:

Thursday night’s interviews are the first conducted entirely after Obama’s widely viewed 30-minute prime-time campaign ad, which ran on several television networks Wednesday evening. Obama held a substantial lead over McCain in last night’s polling, however no greater than what Gallup found on Wednesday.

Second, the ABC/WaPo tracker has the most interesting write-up of the day. It focuses on race and ethnicity and the review is really quite striking:

1. Obama outpaces recent Democratic nominees among white voters;
2. African Americans express near unanimous support for Obama, by 97% to 1%;
3. Latino voters break for Obama by a wide, 68 to 29 percent margin. The key here is the economy, on which nearly two-thirds of Hispanics trust Obama more.

Third, Obama still benefits from an enthusiasm gap, per the Hotline poll:

Today’s Poll shows that 61% of likely voters are supporting their candidate enthusiastically, with Democrats reporting higher enthusiasm for their candidate than Republicans by a 21-point margin, (72% for Democrats, 51% for Republicans).

Finally, on a methodological note, Prof. Charles Franklin has a nice, updated overview on Pollster.com (with graphs) of the different pollsters’ house effects (Trackers and House Effects).