New VA-5 poll nudges our forecast slightly toward McGuire

A new Washington Post/George Mason University Schar School of Policy and Government survey of 600 likely voters in Virginia's 5th District, fielded September 23-28, has Republican Rep. John McGuire at 51 percent and Democrat Tom Perriello at 45 percent.

The poll moved our forecast a little in McGuire's direction. Our model now gives Perriello a 29 in 100 chance of winning the seat, down from 31 percent in the run completed at 7:02 AM ET today. McGuire's chance rose to 71 percent from 69 percent. Our model's average expected margin shifted to R+4.7 from R+4.2.

The change is small, and the race remains uncertain in our model. Its 5th-to-95th percentile range for the final margin runs from R+18.9 to D+9.4, narrowed only slightly from R+18.3 to D+9.9 in the previous run. A Perriello win sits well inside that range. This is one survey, and our forecast treats it as one input among several.

The district's outlook has little bearing on the national picture in our model, which gives Democrats a 99 percent chance of winning a House majority of at least 218 seats, with an average of 245.3 Democratic seats across simulations. That figure is somewhat firmer than it should be. Our simulation correlates error nationally, by census division, by state and within each district, but it does not yet link demographically similar districts in different places, because we lack the data to do so.

Election Day is November 3, 33 days away.