Nate Cohn @Nate_Cohn
Many pollsters have a tougher second screen, particularly late in race. They often give 0 weight to anyone who doesn't say 'very likely' or 'almost certain' to caucus. In our poll, this would have cost Sanders (our Oct. result in par.) W 21 (22) Bu 19 (18) B 16 (17) S 16 (19) — PolitiTweet.org