And exhale slowly. Do it again. Ok, everyone calm? Several of you have emailed me re: the Drudge Report, or other sites, reporting the latest Gallup Poll indicating that the race at the national level is a statistical tie (Gallup has Obama up 49-47, with a 2% margin of error). “Gallup Shock,” trumpets the Drudge headline. What’s going on? Has the race tightened that much? Not according to Nate Silver, who accuses Drudge of “cherry picking” which poll to report in order to reframe the campaign narrative (a tactic Silver knows well, as evidenced by his selective reporting on the debate results.)
For regular readers of this post (and for my students who heard me lecture on this today), this development isn’t necessarily unexpected. Recall my earlier post on Gallup’s continued reliance on samples of registered voters, as opposed to likely voters. Historically, most pollsters move toward samples of likely voters as Election Day draws near, for the simple reason that we want to sample people who are actually going to vote, rather than those who are simply registered to vote. Gallup was the last of the pollsters doing daily tracking polls to make this switch, but they did so this last week.
Generally speaking, Obama does better among polls based on registered voters, but McCain does better among polls of likely voters. The reason is that typically Republicans turn out in a greater proportion to their registered numbers than do Democrats, so when pollsters switch to likely voters samples, they traditionally increase the weighting of Republicans. This year, however, the heightened enthusiasm among voters, especially in the Democratic primary, coupled with a spike in voting registration totals, has led some pollsters to wonder whether the Democrats might in fact turn out in much higher numbers during this cycle. Pollsters are thus left with a dilemma – do they use the traditional procedures that weight Republicans more heavily, or do they adjust their samples to account for what might be a different, more heavily Democratic turnout this year? Rather than choose between the two options, Gallup decided to present both versions of likely voter samples. Under the traditional turnout model, McCain gets a bump, and the race is essentially tied at the national level. But under the new likely voter model developed by Gallup, Obama is comfortably ahead by 6%, 51-45.
So, which is more accurate? One way of finding out is to look at the other national tracking polls. Do they show a movement toward McCain? Yes and no. Three of them show a slight movement toward McCain, but one (Zogby) shows Obama gaining a point and the other three show no movement. Based on this, Silver concludes that there is no real trend toward McCain.
In truth, we simply can’t be sure for at least two reasons. First, and most important, no one really knows what the actual partisan distribution of likely voters is; given the unprecedented registration figures it’s not clear whether the traditional sampling strategies still hold in this election cycle. Second, if there is a movement toward McCain, we need more than two days to be sure that it is happening. But neither can the possibility be dismissed.
Most importantly, to be significant, national trends must translate into gains at the state level, particularly in the battleground states. I don’t see any evidence that this is happening, although because state polls are conducted less frequently, national level trends typically take a couple days to show up at the state level. So my advice is neither to overreact to these polls nor completely dismiss them. Anyone who tells you they know what is happening likely has a partisan axe to grind. My instinct says this race hasn’t tightened, but I have absolutely no evidence to support this claim, and thus my assertion is no better than Silver’s or Drudge’s or any other pundit’s. It is a guess, plain and simple, and should be treated as such.
For now, your best bet is to turn on the Red Sox game – they’ve come down from 7 runs to tie the game in the 8th inning.
Now this is something that should take your breath away.