Polls Gone Wild?

How can you explain the difference between the Pew Research poll and the Gallup polls?

Bush Leads in One Poll, Tied in Another

By WILL LESTER
WASHINGTON (AP) - President Bush has a double-digit lead in one new national poll, but he's tied with Democrat John Kerry in another. Both campaigns say their own polling has the race close, with Bush's people seeing a slight lead for the president.

Kerry and Bush are tied in a Pew Research Center poll taken Sept. 11-14, after Bush was up by 12 points or more from a Pew sample taken Sept. 8-10. A Gallup poll being released early Friday has Bush up 54 percent to 40 in a three-way matchup, with Ralph Nader at 3 percent.