Pollsters can expect to take their share of blame when their campaigns lose, and this year has been no exception. Not long after Barack Obama and Democrats had a strong night on Nov. 6, Republicans began to complain publicly that the polls conducted by their campaigns and by affiliated groups implied considerably more optimistic outcomes for them than actually occurred.
Perhaps these Republicans shouldn’t have been so surprised. When public polls conducted by independent organizations clash with the internal polls released by campaigns, the public polls usually prove more reliable. [cont.]
Nate Silver, FiveThirtyEight (NYT)