Dueling polls came out this week showing almost opposite results in the race for North Carolina’s 9thCongressional District. In a Survey USA poll sponsored by the conservative Civitas Institute, Democrat Dan McCready leads Republican Mark Harris by four point, 45-41. In a New York Times poll, Harris leads McCready by five points, 47-42.
So who’s right? Probably both of them. Both are within the margin of error, so the best interpretation of the polls is that the race is essentially tied. The fact that Mike Pence is coming to the district for Harris indicates that the GOP is not walking away from the race.
The New York Times is doing polls in real time, showing results as the they come in. The project is designed to help people better understand polling methodology and the uncertainty of polling results. Polls today require weighting to get a representative sample and even then the sample might not reflect the people who actually show up to vote. In other words, polling requires a bit of educated guesswork that may or may not be accurate.
The polls each have sample size of more than 500 people, but they come up with differing political environments. In the NYT poll, voters have a positive approval rating of Trump, 52-43. The Civitas poll has Trump underwater by seven points, 44-51.
One of the big differences in the polls is the gender gap. The NYT poll has men supporting Harris by 19 points and women supporting McCready by 12 points. The Civitas poll has women at eight points for McCready and men split evenly. I’ve got to believe men in that part of the world lean a little more Republican than the Civitas poll suggests. I’m not sure it’s 19 points, though.
Both polls were done in the middle of the Kavanaugh hearing so that should not have been a difference. FiveThirtyEight gives both pollsters an “A” rating so the polls themselves should by high quality. Survey USA has been polling North Carolina for a long time and they’ve polled the district this year already. Their weighting may reflect their experience. Still, I think the best way to interpret the race is to call it a toss-up.