The new poll appears to be an outlier -- a conclusion that is supported by other results from the poll showing President Obama with a massive, 17-point lead over former Massachusetts Gov. Mitt Romney. The Roanoke College poll, on the other hand, showed Romney leading Obama by one point.
The NBC News/Marist Virginia poll shows a big edge for Democrats in party identification, which may explain a great deal of the discrepancies between this survey and other polls in the race. Thirty-six percent of voters surveyed said they were Democrats, while 24 percent said they were Republicans. When independents are allocated according to their leanings, 50 percent of respondents are Democrats or lean to Democrats, while 35 percent of voters identify as Republicans or Republican leaners. Democrats held a six-point party ID edge in 2008, according to exit polls.
A closer look at the Virginia crosstabs show a closer race. The two candidates earn similar amounts of support from members of their own parties: Kaine wins 86 percent of Democrats, while Allen captures 85 percent of Republicans. Independents are split evenly, with 41 percent supporting each candidate.
The Ohio poll also shows a similar party-ID discrepancy, though the poll shows a similar overall result in the head-to-head matchup. Mandel, in the new NBC News/Marist poll, runs virtually even with Brown among independent voters, trailing by four percentage points. In the Quinnipiac poll, Mandel trailed Brown among independents by 23 points.
The NBC News/Marist polls were conducted Feb. 29-Mar. 2. In Ohio, 3,079 registered voters were surveyed, for a margin of error of plus-or-minus 1.8 percentage points. The Virginia poll surveyed 2,518 registered voters, for a margin of error of plus-or-minus 2.0 percentage points.