Nate Cohn @Nate_Cohn
This latter result, with the tight second screen, is closest methodologically to, say, Selzer's screen. And indeed, she had Sanders/Biden at 16/15 two weeks later. The result after the 1st screen (no second screen), is more like Emerson, which had Biden/Sanders in 1st kn Dec.. — PolitiTweet.org