2016 Postmortem
In reply to the discussion: New CBS News New Hampshire poll -- Sanders CRUSHING at 56% to Clinton 42% for a 14% lead! [View all]Attorney in Texas
(3,373 posts)The fact that Sanders has an 8.6% aggregate lead in New Hampshire at Real Clear Politics, but only a 4.3% aggregate lead in New Hampshire according to Pollster is due, in part, to the stricter methodology requirements imposed over at Real Clear Politics.
Nate Silver over at 538 discussed this phenomenon in connection with Trump's poll numbers (how he does better in poor methodology polls and does worse in polls that employ more accepted methods), and the same is true for Clinton's polling.
If you look at a graph of all the polls (the best, the good-but-flawed, and the crap), Sanders has an aggregate 4.3% lead:
If you focus on likely voters (drop the polls of all adults and polls of all registered voters), Sanders' aggregate lead grows to 4.9%:
If you drop the robo-call polls, which employ the most doubtful of methodologies, Sanders' aggregate lead grows again to 7.2%:
If you drop the pollsters who have not conducted at least 4 polls in New Hampshire (drop the one-off and infrequent pollsters), Sanders' aggregate lead grows to 8%:
If you narrow down to the live phone (landline and cell) polling of the most freuent pollster, Sanders' lead peaks at 10.6%:
And this 10.6% live phone polling lead for Sanders is bigger than the internet-polling 10.1% lead in the CBS News polls:
Contrast this with a graph that includes only robo-call polls, which give Clinton the lead in New Hampshire (and make the aggregation of polls look like a closer race than the more reliable polls suggest):