As I pointed out in my super-post, there were 17 total polls, and nearly ALL of them skewed towards the Democrats. That clearly shows an error of some type.
Or, it shows a successful repression of democratic votes by the republicans from the accurate measurement by the polls. You aren't interested in the facts, though, you have said before.
Polls vary. There are the idealized polls with random sampling and such, and then there are various compromises made for real world needs. Just defining what you want in a poll is tricky.
Do you want to know who Americans want as president if they voted now? Do you want to filter that only by people of voting age? Only registered voters? Do you want to take into account things like how much more likely older registered voters are to vote than younger ones? Adjust for other factors affecting likeliness to vote?
Do you want to try and account for other factors that may affect turnout - for example, a gay marriage amendment that's expected to increase right-wing turnout? At some point, if you try to accurately predict who is going to vote, you have to make more and more guesses and estimates how to 'weight' the polling.
If you don't weight it, you have big gaps between the people who can vote and the people who vote, making the poll very, very inaccurate for predicting the election.
That's where the great accuracy of *exit* polls comes into play. No more guessing who is going to vote - it asks the voters who did.
And it's why they're so accurate - and the bottom line is that a big gap between exit polls and election results indicates election fraud, and is why the republicans put the big propagandists onto coming up with attacks on the exit polls.
Are there questions that should be asked on te exit polls? Yes. Will you get the accurate info from the ultra-partisan republicans who only care about proving one answer and will not consider any evidence that there was any fraud? No.
