Mitt Romney is gaining ground in Ohio, Virginia and Florida, but President Obama stills leads all three in the latest NBC News/Marist polls.
Romney campaigned Thursday in a fourth swing state, Pennsylvania, visiting a charter school in mostly African-American West Philadelphia.
While there he dismissed the idea that smaller classes lead to higher achievement.
The visit came hours after President Obama called Romney "out of touch" on economics for pushing the same less-tax, less-regulation plan of George W. Bush.
"Most good business people I know, if something doesn't work, they do something different," Mr. Obama said. "So he must either think that there's going to be a different result, or he's hoping you don't
remember what happened the last time we tried it his way."