The reality is that the electorate is changing. In 2012, many Republicans thought there was no way that turnout among groups like African-Americans or the young could possibly keep pace with 2008. They were wrong. The remarkably effective turnout machine of the Obama campaign proved they could continue to create the electorate they needed to win. And without a clear, evidence-based model for who is and isn’t likely to vote, new research suggests the ups and downs you see in your polling might just be sampling bias (PDF) rather than real movement of opinion.

In the 2013 race for governor in Virginia, one pollster did get a tough race right on the money—Democratic pollster Geoff Garin. He used previous vote history as just one of a variety of factors, built on sophisticated modeling, to assess someone’s likelihood of voting. Or take Harry Reid’s pollster Mark Mellman, who has said that he is less concerned with identifying if individuals are or aren’t “likely voters” but instead focuses on figuring out what the “likely electorate” will be and building his samples accordingly. In interviews this week, McLaughlin noted that “polls don’t predict turnout,” but with the use of good modeling and smarter analytics, it seems top Democrats might disagree.