JLF’s John Hood takes a fascinating look at several well known pollsters and the characteristics of each.
On the FiveThirtyEight.com letter grading system, Survey USA is one of the few pollsters to get an A. Elon University gets a B. High Point University, PPP, and National Research each get a B-minus.
While these are the pollsters that produce the greatest amount of survey research on North Carolina issues and opinions, the Senate race between Kay Hagan and Thom Tillis has certainly drawn lots of other pollsters into the state this year. Among the ones you probably see or hear about most often, the highest-ranked are ABC News/Washington Post, CNN/Opinion Research, and NBC News/Wall Street Journal, all of which get A-minuses in the pollster rankings. Mason-Dixon, Fox News, Pew Research Center, and CBS/New York Times also compare fairly well, getting Bs. Less impressive in recent election cycles have been surveys from Gallup (C+), Rasmussen Reports (C), Gravis Marketing (C), and Harris Interactive (D+).
Even the most accurate election pollsters produce some screwy samples or weight them unwisely. In addition to ranking them by accuracy, FiveThirtyEight.com also provides estimates of the average partisan bias. For top-flight pollsters, the bias is often very small. In recent elections, for example, Survey USA’s predictions have been slightly (0.2 percent) more Republican than electoral outcomes. So have predictions by National Research (+0.5 percent Republican) and — get this —PPP (+0.7 percent Republican). The Elon University poll, on the other hand, has leaned slightly Democratic (0.2 percent) while the High Point University poll has been among the few with no partisan bias at all.
Keep all this in mind as you look at poll results leading up to the November election.
