They most certainly do and they weigh/sample the polls accordingly. They did it with Obama in 2012 (rightfully so). Are you aware that a few polls have taken a R+1 sample and then changed it to Dem+8 and +4? Whats the reason for that? Explain Awhy some polls that sample Dem+1 or 0 then sample more women or blacks or college educated or other?
These are things that are happening all the time. Can you explain why? Can you explain why every poll that's randomly taken has consistently more Dems or other demographics that favor Clinton? How can that be?
Imagine if a poll that came out sampled Republicans at +1 or greater. The internetz would explode with "What BS is this!!?" "BS poll!!!!" etc etc
Because polls sample, and weight if necessary, by demographics such as sex, race and age. So if a poll has a R+1 sample but is weighted by other demographics to hit targeted voter turnout then you end up with the Dem +4 or Dem +8. The electorate has been trending less white for 30+ by a few percentage points every Presidential Election, there is no reason to think that won't continue this year.
You're making my point. They are using the 2012 Obama turnout which will turn out WAY higher than Clintons. Democrats aren't getting to the polls like they were. They are down by 4.5M people since 2008. Thats a 20% decrease. The tables have turned (Repubs getting out to vote at record numbers, while Dems cool off) and the pollsters aren't even taking this into account. Again, that is a critical mistake. You have to see and acknowledge that. It only makes sense.
Can you explain how the Washington Post can have her up by 12 points and 72 hours, yes HOURS, later she's only up by 6? I mean really Ace?. Don't you find that a little "weird"?