So if you are an omnivorous political junkie who likes election-night drama, or just someone looking for an excuse to ignore the president’s Syria speech tonight, you should read Nate Cohn’s piece at TNR on the uncertainties surrounding New York’s Democratic mayoral primary. The polls have consistently shown for a couple of weeks now that Bill de Blasio is ascending, Christine Quinn is descending, and Bill Thompson holding steady, with de Blasio’s rise giving him a decent and ever-increasing chance of avoiding a runoff and even higher odds of winning one if he doesn’t.
So where’s the drama?
As Cohn points out, relying on polls in urban local government primaries is a perilous endeavor:
Data-driven electoral analysis gets harder and harder the farther you get from a two-party presidential election. There are fewer polls, and they’re less accurate. Partisanship becomes less powerful. Turnout is less predictable. You can’t handicap the race with well established “fundamentals,” like national economic growth. And in the place of partisanship and fundamentals, candidate quality and local politics—where traditional reporters thrive—prevail….
[I]t’s hard to think of a place tougher to poll than New York City: Urban areas have low response rates; non-white and young people have low response rates; people who don’t speak English have low response rates, and so on. Low and variable turnout makes it even worse. There are about 4.3 million registered voters in New York City, of which 3 million are registered Democrats, of which anywhere from 330,000 to 1.1 million have participated in Democratic primaries over the last 24 years. Most expect turnout to fall somewhere between those two extremes. If we split the difference and go with 700,000 voters, that’s about 16 percent of registered voters. So if a pollster got about 1,000 registered voters—like the average national survey—they would be left with only a tiny number of likely Democratic primary voters, with an unacceptable margin of error, especially since many of the hard-to-reach voters are Democrats.
When multiple polls are pretty much showing the same trends, however–as they are in New York right now–the odds of any given poll being an outlier drop. But they don’t disappear.
The other thing about New York elections, though, is that they are massively over-reported and over-analyzed. So if something unforeseen happens tonight, it will be over-interpreted as well. And the first thing we’ll hear is how the polls turned out to be unreliable, which is what we should have understood from the get-go.