NJ Watch (Friday) Plus an Automated vs. Live Interviewer Bonus

10/30/2009 04:38 pm ET | Updated May 25, 2011

The most recent polling in New Jersey shows an excruciatingly close race between incumbent Democrat Jon Corzine and Republican challenger Chris Christie. As of this writing, our standard trend estimate (below) puts Corzine "ahead" by a negligible 0.8% (41.4% to 40.6%). The more sensitive setting on our smoothing tool makes the Corzine margin slightly narrower (0.6%), the less sensitive setting makes it slightly larger (0.9%). Any way you look at it though, the differences between the estimates -- and more importantly, between Corzine and Christie -- are virtually meaningless.  Right now, the current polling snapshot of this race is a close as these things get.

For perspective on the closeness of the margin you might want to stroll down memory lane and revisit my final Election Day update from Tuesday, November 4, 2008. We showed only four states where the Obama-McCain margin on our trend-estimates was less than 2 percentage points, and the leader ultimately won the state in 2 of 4 states. So a margin of under two percentage points puts us well within true toss-up territory in terms of predictive accuracy, especially with a weekend of polling still to go.

Understandably, the close nature of the race has political junkies turning these numbers upside down and reading every possible tea leaf and in search of the key to the outcome. After doing much of the same (while out with the flu) the last few days, the best answer I can give based on the empirical evidence -- for the moment at least -- is that this race is currently looking very close.

Are things trending toward Corzine? Yes, when compared to early September, our chart indicates a decline of roughly four percentage points for Christie and an increase of roughly three points for Corzine. Over the course of the summer, Christie had been dropping (from a high of roughly 49% in early July), while Corzine remained flat.

What is less clear is whether the closing trend has continued over the last two weeks. As of this writing, only three pollsters have tracked more than once since mid-October, allowing apples-to-apples trend comparisons. Two, SurveyUSA and Democracy Corps -- show Corzine's margin two percentage points better. One, Rasmussen, shows it one point worse. None of these differences are statistically significant alone and the patterns are obviously small and inconsistent.

That said, the trend over the next four days may not be as smooth, and the Daggett "wild card" that everyone has focused on for the last few months is the reason. Consider at least three ways that the Daggett effect leaves us even more uncertain about the outcome:

Individual level uncertainty -- The Monmouth University Polling Institute reported yesterday on a focus group they convened earlier this week in Edison, NJ among voters who are still either undecided or just leaning to a candidate. While they explicitly warn against treating the findings as representative of all undecided voters, the most clear finding was a sense of unhappiness with both major candidates: "These voters claim that this is the most difficult election choice they have ever faced. Nearly all said that Jon Corzine has not done a good enough job to deserve reelection. They simply have not heard enough from Chris Christie to cast their lot with him." Their final decision about Daggett, the report says, may come down to whether he has a chance of winning.

Aggregate level uncertainty -- One statistic worth pondering: On the last ten polls, all conducted in the last week, the portion of the electorate that is either undecided or supporting a candidate other than Corzine or Christie averages 16.5% (with a range of 11% to 23%). As a crude measure of voter uncertainty, that's considerably more than 5% or so we saw at this stage of last year's presidential election.

Measurement artifacts? -- Complicating this issue even further are the measurement challenges that pollsters face when testing lesser known independent candidates, especially when voters are unhappy with the top two choices. Offer just three choices and no explicit undecided category and some undecided voters will choose the independent as their way of expressing uncertainty. On the other hand, fail to prompt for the independent and you may measure a number that's much lower (see, for example, the intriguing experiment embedded in the Fairleigh Dickinson poll). Reality likely falls somewhere in between. And no one can be certain of the effect that the other 9 candidates will have.

And finally, there is the intriguing pattern noted earlier this week by PPP's Tom Jensen and explored last night by Nate Silver. Christie has done consistently better on telephone polls conducted using an automated, recorded voice than on those using live interviewers. Using the filter tool on our chart, as of this writing, Christie runs roughly three points ahead of Corzine on the automated polls, but Corzine runs a little less than three points ahead on live interviewer polls. The chart below, which Charles Franklin kindly prepared this afternoon, shows that the difference has been consistent throughout the race (his margins are likely different than on our interactive chart due to his use of slightly different smoothing levels).


We also see a similar though far less pronounced and consistent effect in Virginia, and then only since Labor Day.


What this effect is about, and what it portends for the outcome in New Jersey, I cannot say. Nate Silver has some plausible speculation about automated surveys being potentially more sensitive to an enthusiasm gap between Republicans and Democrats, although if that is true, I have no explanation for why we saw no such consistent difference between automated and live interviewer surveys in the Obama-McCain polling last year. We should have new surveys over the weekend or on Monday from all three automated pollsters in New Jersey (SurveyUSA, PPP and Rasmussen) and from at least three of the live-interviewer polls. So this phenomenon will be interesting to watch.

Either way, the combination of a very close snapshot and many indicators of potential volatility makes for a very uncertain outcome.