By Adam Geller, National Research Inc.
I’d like to contribute a few thoughts on the performance of the public polls during the recently concluded New Jersey Gubernatorial race. On this topic, I bring a unique perspective, as the pollster for the Christie campaign, and I’d like to offer my thoughts not as any type of authoritarian, but rather to contribute to an important professional discussion.
I should mention that, for what it’s worth, some observers may have been surprised by the results on November 3rd, but neither Governor Elect Christie nor his advisers were surprised.
Before the cement hardens and ink dries on the post election wrap up, let me offer the following five thoughts:
1. The automated polls were more accurate than the live interview public polls, due in part to the methodology of the live interview polls.
From polls that were in the field for an entire week (Quinnipiac) or even longer (FDU), to polls that oversampled Democrats (Democracy Corp, among several others) to polls that asked every single name in the ballot (Suffolk), an essential reason for the poor performance of the live interview polls had less to do with the fact that a live person was administering the poll and more to do with methodological issues.
2. The partisan spread in the polls ought to be reported up front.
Some public pollsters make it difficult to determine how many Republicans, Democrats and unaffiliated voters they interviewed. Why not just put it into the toplines? Reporters and bloggers should demand this before they report on the results. Not to pick on Quinnipiac, but they had Corzine and Christie winning about the same amount of their own partisans, and they had Christie winning Independents by 15 percentage points, and yet they STILL had Christie trailing overall by 5 points. Quinnipiac did not publish their partisan spread, but then an astute blogger was able to ascertain the fact that there were, in fact, too many Democrats in the sample. Other polls, notably Democracy Corp, regularly produced samples with too many Democrats (though, in their parlance, some of these were “Independent – Lean Democrat”). That their sample was loaded up with Democrats had the obvious effect on their results. Whether this was intentional or not, I would leave to others to speculate.
3. In general, RDD (random digit dialing) methodology is a bad choice in New Jersey, if the goal is predictive accuracy.
In New Jersey, there are many undeclared voters (commonly but mistakenly referred to as Independents). These undeclared voters identify themselves as Republicans or Democrats – even though they are not registered that way. In our polls, we frequently showed a Democrat registration advantage that matched their actual registration advantage – but when it came to partisan ID, the spread was more like a six point Democrat advantage. By using a voter list, we knew how a respondent was registered – and by seeing how they ID’s themselves, we gained insight into the relative behavioral trends of undeclared voters and even registered Democrats who were self identifying as Independents. Public pollsters who dialed RDD missed this. Partisan identification in New Jersey is not enough, if the goal is to “get it right.”
4. The public polls oversampled NON voters.
Again, this is a function of RDD versus voter list dialing. It is easy for someone to tell a pollster they are “very likely” to vote. With no vote history and no other nuanced questions, the poll taker has little choice but to trust the respondent. Pollsters who use voter lists have the benefit on knowing exactly how many general elections a respondent may have voted in over the past five years, or when they registered. By asking several types of motivation questions, the pollster can construct turnout models that will have a better predictive capacity. The public polls did not seem to do this.
To this end, we had heard all about the “surge strategy” that the Corzine campaign was going to employ. This refers to targeting “one time Obama voters” and driving them out in force on election day. With voter lists, we were easily able to incorporate some “surge targets” into our sample. After running our turnout models, we saw no evidence that the surge voters would be game changers.
5. The Daggett effect was overstated in the public polls.
Conventional wisdom holds that Independent candidates underperform on election day. But the reality is, many analysts could have easily predicted Daggett’s collapse, based not on history, but on simple a simple derivative crosstab: for example, voters who were certain to vote for Daggett AND had a very favorable opinion of him. They could have asked a “blind ballot” where none of the candidate choices were read. We did these things – and we estimated Daggett’s true level of support to be around 6%.
None of this is meant to pick on the “live interview” public pollsters. For the most part, these polls are conducted and analyzed by seasoned research professionals. But in non-Presidential years, RDD methodology can lead to inaccurate results, which can then lead to inaccurate analysis. It is tough to conclude that the automated polls are somehow superior to live interview polls, given the methodological issues I’ve outlined.
What does it mean for next year? At the very least, journalists, bloggers and reporters need to ask more questions about the methodology and construction of the poll sample. They need to understand the partisan spread, and the extent to which it conforms to reality. They need to know how long the survey was in the field. They also need to beware of polls being released that are designed to manipulate opinion rather than measure it. They need to ask if certain polls are being constructed to reflect what is happening, or if they are being constructed to reflect what the poll sponsor would LIKE to happen. The public polls add to the dialogue, and given their ever increasing contributing role, we all ought to be more demanding when reporting their results.
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