Pollsters don’t like being very different from their competitors so they often fudge the turnout numbers so they don’t go out on a limb. Going out on a limb is great if you’re right. If you’re wrong, you look like an idiot. If you want to have an ongoing business, you don’t want to go out on a limb too often. So what looks like a consensus–an average of independent results, can actually represent, groupthink But that’s true of the national results, too.
This is from Professor Russ Roberts at the Cafe Hayek. This serves as another reason to look at surveys or polling trends with a skeptical eye.