Mercyhurst's findings are roughly consistent with a pair of polls conducted in the state over the last two weeks. The Inquirer Pennsylvania Poll, published Sept. 16, had Obama leading Romney by 50 percent to 39 percent, and last Tuesday's Allentown Morning Call/Muhlenberg College Poll put Obama's edge at 50 percent to 41 percent.
Those results are within the range of other recent polls - including one by Rasmussen Reports, considered a GOP-leaning firm, which put Obama up by 12 points in the state. The news website Real Clear Politics, which aggregates polling, says Obama's lead in recent Pennsylvania polls averaged 8 percentage points. The same site put Obama's average lead in recent nationwide polls at just 3.7 percent as of Monday.
A poll published Sunday in the Pittsburgh Tribune-Review found a much closer race in Pennsylvania - with Obama leading by 47 percent to 45 percent, and 6 percent undecided. That survey of 800 likely voters was conducted from last Tuesday to Thursday by Susquehanna Polling & Research and had a margin of error of plus or minus 3.4 percentage points.
Susquehanna, a Republican-oriented firm based in Harrisburg, says its results differ because it based its sampling on a forecast of a lower voter turnout than in 2008. The same firm reported similarly close results last week in a poll commissioned by the state GOP.
"Barack Obama is in a good position in the state, but the race isn't over," said Joseph Morris, director of the Mercyhurst Center for Applied Politics, which conducted the most recent poll for the Erie-based school.
Among the other findings in the Mercyhurst poll:
Of respondents who said they would vote for Obama, 63 percent said they strongly supported him; 17 percent said their vote was more motivated by opposition to Romney.
Among those who will vote for Romney, 43 percent said they strongly supported him, but nearly as many - 39 percent - told pollsters they were voting for Romney because they opposed Obama.
Just 49 percent of Pennsylvania's likely voters said they had heard of super PACs, which can raise and spend unlimited amounts of money to influence elections and have been a major factor in the 2012 campaign.
Of those who knew about the groups, 68 percent said they should not be unlimited in their spending ability, and 71 percent said the groups should be required to disclose the names of their donors. And 63 percent said super PACs had a negative effect on the presidential race.
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