On Allocating Undecided Voters

 At fivethirtyeight.com, Nate Silver has a formula for allocating undecideds.  It is a pretty simple formula.  He looks at how Obama overperformed or underperformed relative to the polls in the Democratic primaries, and then applies the formula to the general election.  I’m having trouble replicating his results – the best I could get it was an r-square of .61, with only three of the variables at significant at 95%, but that could be due to different datasets used and different estimates of variables (I’m also not entirely certain when he’s using dummy variables). 

There are a lot of little nits one could make (Kentucky doesn’t border Illinois?), and I think there may be some multi-collinearity jacking up his r-square (hard to say), but the major complaint is this:  One cannot make the jump from primary electorate to general electorate without first knowing who the undecideds were in the primary, and then determining that the same groups are similarly undecided in general.  In other words, if 10% of the undecideds in SC were African American in the primary (plausible, given Obama’s late surge and a choice between two Democrats) but only 1% of the undecideds are African American now (again, plausible, though I could make an argument either way – maybe the 10% of AA’s who vote Republican are all undecided now), it is hard to predict with accuracy how the undecideds will break overall in the general based on how they broke in the primary. 

 Even if you could, it is difficult to draw hard conclusions, because it is impossible to know, say, if the African Americans who are undecided in the general share salient characteristics with African Americans who were undecided in the primary (ie, if the undecided AAs today typically vote Republican, they may well be more likely to break toward McCain than AAs were to break toward Hillary, though again, I could make the argument either way). 

 And what if pollsters are correcting now for an anticipated surge in AA turnout?  What happens when we move from an electorate where AAs comprise around 50% of the electorate to one where AAs will comprise no more than 30%, save in a few states?  Won’t this mute any reverse-Bradley effect significantly?

 And unfortunately, at the state level, this is impossible to do at more than the anecdotal level.  Only about 5% of any given state self-describes as “undecided” at this point, so you’re allocating a very small dataset.  And given that subsamples have even larger margins of error than samples, it becomes impossible to say scientifically that “5% of the undecideds are white, 1% of the undecideds are African American” and make any type of conclusions about the makeup of undecideds.   If you see the same pattern repeating in poll after poll (as we do with older voters being more undecided), then you can make some observational comments, but you can’t make scientific comments. (Yes, error margins shrink as you approach an extreme, but not enough to completely fix this problem).

 Silver recognizes this, and writes that “it does not necessarily follow that the patterns exhibited by undecided voters in the primaries will match those in the general election.”  His response is a non-answer:  “based both on my research and on what I've been hearing from people on the ground, it's apparent that the public polling in general is not terrific, and that if we have an instinct about where the polls are more likely to come in high or low, we probably ought to follow it.”  Which is fine, but for a regression model that is supposed to be scientific and non-arbitrary, simply going with our instincts seems to be awfully arbitrary (especially where part of the model for what our instincts are is going to be based on polling data regarding the number of undecideds).

 I do think, though, that we can glean some information about the undecideds at the national level.  Gallup is kind enough to give the demographic crosstabs for the entire weeks at a time.  This works out to around 6,000 voters.  The crosstabs then, even for a group that makes up only 10% of the population (like African Americans), would have reasonable error margins (around +/- 4% here).  We can make some observations  -- though it is difficult to draw definitive conclusions -- based on this:

 Looking at it this way, we see the following:

Age:

18-29: 5% undecided

30-49: 7% undecided

50-64: 7% undecided

65+:    11% undecided

 Church Attendance (whites only):

Weekly: 8% undecided

Monthly: 7% undecided

Seldom/Never: 8% undecided

 Education:

HS or less: 11% undecided

Some College: 7% undecided

College:  5% undecided

Postgrad:  5% undecided

 Education (whites only):

HS or less: 12% undecided

Some College: 6% undecided

College:  5% undecided

Postgrad:  5% undecided

 Gender:

Male: 7% undecided

Female: 9% undecided

 Political Party/Ideology:

LibDems: 2% undecided

ModDems: 7% undecided

ConsDems: 10% undecided

Pure Indep: 41% undecided

Lib/ModReps: 5% undecided

ConsReps: 2% undecided

 Race:

Non-Hisp White: 8% undecided

Non-Hisp Black: 3% undecided

Hisp: 10% undecided

Region:

East:  10%

Midwest: 8%

South: 7%

West: 6%

 We can argue about the meaning of this, but I don’t think it bodes well for Obama.  There are almost no black undecideds, and there are few post-college educated undecideds.  Very few youth are undecided.  These are his wheelhouse. 

 Instead we have an undecided electorate that tends to be older (do you REALLY want to run ads making fun of McCain for not knowing how to use a computer?), less educated (especially among whites), and white or Hispanic.  There are also a lot of undecided conservative Democrats.  These are groups with which Obama struggled in the primary; to the extent primary voting is indicative of how undecideds will break, this may indicate a serious problem for Obama getting to 50%+1.  They are also disproportionately in the East, where Silver did find a Bradley effect (depending on how "East" is defined in this dataset, of course).

 I also note with interest the high number of “pure independents” who are undecided.  This group has by far the highest proportion of undecided voters.  This seems to support Jay Cost’s theory that the people who are left to make up their minds are not ideological people, that they are people who won’t take partisan cues, and that they might not break until very late in the race.

 Finally I will also note Jay’s more recent post regarding reflections on the state of the race, which denotes Rasmussen, Gallup, and “all other national polls” averaged over time.  Note that in Rasmussen and “all others,” Obama has received almost no undecided voters.  In fact, he has marginally declined from June to the Conventions, and is now back to where he was in June, while McCain has made steady upward progress.  In Gallup that is not the case, but against all other pollsters, that would seem to make it an outlier (I do wonder why Jay didn’t average Rasmussen and Gallup for the month).

 Again, it is impossible to predict with any certainty how the undecideds will break.  But there are certainly some danger signs in here for the Obama campaign.