John McCain is likely to underperform in exit polls, which historically favor Democrats, writes McCain’s pollster Bill McInturff in a memo reprinted by CQ Insider. In the last two presidential elections, exit polls have shown the Democratic candidate doing better than he ultimately did in the real vote count. There’s a simple reason for this: Democrats are more willing than Republicans to participate in exit polls.
McInturff notes that the skewing effect occurs at the state level as well that national: support for John Kerry in 2004 was exaggerated by exit polls in 26 states, but for George W. Bush in only four. High turnout tends to skew exit polls even more, so voters need to be on guard against thinking the race is decided before it is.