i was listening to npr this morning and i'll admit i was gloating a bit. they did an interview with a couple of professional pollsters and one of them brought up the idea of "herding." herding occurs when a poll's results seem out of step with the results of competing polls. the results are "adjusted" so that they are more in line with what other polls are reporting.
the blase attitude of this professional pollster with regards to admitting that it was a regular enough occurrence for poll results to be adjusted to match other polls that there was a name for it was shocking to me. in fact- and i'm being honest here- there was nothing in this entire election cycle that shocked me more than a pollster admitting that intentionally adjusting results to match an established narrative was common practive.
i really can't understand why anyone would value a poll if they were aware that it's results might have been adjusted so that they "make more sense."
edit: link requested by mod
morning edition for wednesday, november 8, 2016 the segment in question is titled hillary clinton concedes; donald trump is president-elect. interview with democratic pollster margie omero begins at 1:23 discussion of herding at 4:53.
OMERO: I mean, there's a phenomenon called herding, where if you are releasing public polling, you don't want to be the person who has Trump up 1 if everyone else has her up 3 or 4, even though that's not a massive difference in the scheme of things. But it is ultimately a difference with a very big impact.
INSKEEP: Meaning that they might massage their numbers a little bit to not look so bad, is that what you mean by herding?
OMERO: Well, we're looking at - massage sounds a little pejorative. But we're looking at the final result after it's been polished. It's come out of the field. They've put it in a release. They've weighed it. And there's just different - you just have different assumptions about what the electorate's going to be - look like because you don't actually know. It doesn't exist yet.
another older article about herding from nate silvers fivethirtyeight blog- Here’s Proof Some Pollsters Are Putting A Thumb On The Scale