How Wrong Were 2014 Polls, Really?

An excerpt from The Surge: 2014’s Big GOP Win and What It Means for the Next Presidential Election (Rowman & Littlefield):

Democrats lost big in the 2014 elections, but in the aftermath, polling also took a hit for largely understating the size of Republicans’ win. While most polls and poll-based models correctly forecast that Republicans would win a Senate majority, they often suggested closer contests and generally understated GOP margins. …

How wrong were the polls, really? CONT.

Mark Blumenthal & Ariel Edwards-Levy, Huffington Post