According to the exit polls, 26 percent of the electorate in last week’s midterms consisted of white evangelicals. Yet white evangelicals make up just 15.3 percent of the U.S. adult population, according to PRRI’s widely used survey data. What gives?....

All in all, there’s no reason to think that this situation has changed since 2008. By my back-of-the-envelope calculation, one-third of the “white evangelicals” who voted last week were not evangelicals in the denominational sense. And that covers most of the gap between PRRI’s number of white evangelicals and the exit polls’.