Why the divergence? One reason is the margin of error, which can skew each candidate’s percentage as much as four points either way. Also, the latest polls reflect a different base-no longer just “registered” voters, but those whose answers to a series of questions suggest that they are most “likely” to vote.
CBS says that because Gallup polls voters between 5 p.m. and 9 p.m., it may miss young and single voters who tend to go out in the evening. But Gallup pollster Larry Hugick says it goes after young voters first. And what about the “undecideds”? Analysis of past elections indicates that the last fence-sitters tend to go heavily for the challenger.
