Whit Ayres’ comments to WBUR’s Here and Now show on the incumbency effect as it relates to 2016 polling:
“There’s a well-established principle in polling, with incumbents running for re-election, that what you see is what you get. In other words, if you’re at 48 as an incumbent, and your opponent is 45, we will frequently tell our incumbent candidates that they’re in trouble… The reason is that frequently incumbents get the number at the polls that they have on the final survey.
Their opponents are generally not saddled with the image of incumbency, so frequently, undecided voters go disproportionately to the challenger. And the issue here is whether or not Hillary Clinton was, if not technically an incumbent, effectively an incumbent running for the third term of Barrack Obama… It seems like more than a coincidence that the number she had in the average of polls at the end of the race is remarkably similar to where she ended up on the final ballot. But Trump made substantial gains, as frequently challengers do.”
To read the full excerpt, please click here.