New VA-1 poll moves our forecast to a near coin flip

A Washington Post/George Mason University Schar School of Policy and Government survey of 609 likely voters in Virginia's 1st District, fielded September 23-28, puts Democrat Shannon Taylor at 50% and Republican Rep. Rob Wittman at 46%. That gap is small for a sample of this size. The race is close.

The poll moved our forecast. Our model now gives Taylor a 49 in 100 chance of winning the seat, up from 41% in the run published earlier this morning. Wittman's chance falls from 59% to 51%. Our model's expected margin shifts from R+2.0 to R+0.3.

Our last look at this race found that new polling left the forecast where it was. This survey did not. It is the only new poll in this update, and it accounts for the change.

The outcomes our model considers plausible remain wide. Its 5th-to-95th percentile range now runs from R+14.6 to D+13.9, compared with R+16.1 to D+12.2 before. A single district poll can shift the estimate, but it does not settle a race our model still treats as roughly even, with 33 days until the election.

Nationally, our model gives Democrats a 99% chance of winning a House majority, which requires 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 by district, but it does not yet link demographically similar districts in different places, because we lack the data to do so.