Three Siena ballot tests put Begich ahead, and our Alaska forecast now favors him

Our forecast for Alaska's at-large House seat has changed sides. Our model now gives Republican Rep. Nick Begich III a 57 in 100 chance of winning, up from 32% in the run published at 4:32 AM ET on October 3. Independent Bill Hill's chance fell from 68% to 43%. Our model gives the Democratic line 0%, unchanged.

The movement follows three ballot tests from The New York Times/Siena University, all fielded September 24 to October 1 among likely voters. In a head-to-head version with 476 respondents, Begich had 53.0% and Hill 47.0%. In a version with 487 respondents that also listed a Democrat and other candidates, Begich had 48.9%, Hill 36.8%, the Democrat 8.6% and others 5.8%. A third version, with 504 respondents, showed Begich at 46.6%, Hill at 35.1%, the Democrat at 8.2% and others at 5.5%.

The head-to-head is the closest of the three, at about 6 points. The two versions with a fuller field show Begich ahead by more than 11 points, with Hill's share about 10 points lower than in the two-way test.

Our model's average margin moved from I+4.0 to R+1.5. That is still close, and the uncertainty is wide. Our 5th-to-95th percentile range now runs from R+15.5 to I+12.5, compared with R+10.1 to I+18.0 in the earlier run.

The seat matters less to the national picture than to the state. Our model gives Democrats a 99% chance of winning a House majority, with a mean of 245.1 Democratic seats against the 218 needed. That probability is somewhat firmer than it should be. Our simulation does not yet link the errors of demographically similar districts in different parts of the country, because we lack the data to do so.