This thread is perfect evidence of why... because they are held accountable for only one poll - the last one.
So even though Pew had Obama +16 polls for the final weeks, they are labeled “acurrate” because they issued a +6 poll at the last minute. Same with CBS and many others.
The lesson is to watch Rasmussen. These other polls are all over the place, and I think a lot of it is for manipulation purposes. Rasmussen polling is very much steady as she shows, which is more reflective of reality than Pew/Zogby/Gallup/CBS polling with 10 point shifts in just days.
“This thread is perfect evidence of why... because they are held accountable for only one poll - the last one.”
You are cherrypicking though. I don’t pay attention to one poll. I pay attention to the average. The industry average stayed pretty constant. There was no gigantic move at the last second.
Look at the RCP averages. No big swing period.
http://www.realclearpolitics.com/epolls/2008/president/us/general_election_mccain_vs_obama-225.html