Democrats hold a 94% House chance in our model, 43% in the Senate

Our model gives Democrats a 94 in 100 chance of winning a House majority and a 43 percent chance of winning Senate control as of 6:30 AM ET on August 29. The mean House outcome in our simulations is 241.3 Democratic seats against the 218 needed for a majority. The Senate is closer to even in seats than in odds: our mean is 49.9 Democratic seats, one short of the 51 Democrats need, while Republicans need 50 because the vice president is a Republican and a 50-50 tie resolves their way.

Our generic ballot average is D+6.6, drawn from 22 polls fielded within the last 45 days.

One note on the House number. Our simulation draws error at four correlated levels: one national, one for each census division, one for each state, and one for each district on its own. It does not include a term linking demographically similar districts in different places, because we have no cluster data for this run. That missing layer means our 94 percent is marginally firmer than a fuller decomposition would leave it. We have not measured the size of the gap and are not adjusting for it.

The largest single movement on the board is AK-1, where the Democratic win probability fell 73.5 points, from 74 percent to effectively zero. TX-15 moved the other way, up 17 points to 52 percent from 35. Ohio's Senate race moved 13.1 points toward Republicans, with the Democratic chance now 44 percent, down from 57. OH-7 slipped nine points to 51 percent and AZ-2 fell 8.4 points to 42 percent. The Texas Senate race moved 7.8 points the other direction, to a 66 percent Democratic chance from 58.

Recent state polling is consistent with that Texas figure. Texas Public Opinion Research surveyed 1,000 likely voters August 21-24 and found James Talarico at 48 percent to Ken Paxton's 42. In New Hampshire, a University of New Hampshire survey of 1,878 likely voters, fielded August 20-24, put Chris Pappas at 45 percent and Scott Brown at 40. The same pollster's Massachusetts survey of 881 likely voters over the same dates had Ed Markey at 49 percent and John Deaton at 30. In Iowa, Suffolk University polled 500 likely voters August 20-23 and found Ashley Hinson at 45 percent and Josh Turek at 41, a margin narrow enough at that sample size to leave the race close.

Quantus Insights released several reads of OH-1 from a single sample of 509 likely voters fielded August 21-24. Across the versions, Greg Landsman ran between 46.5 and 52 percent and Eric Conroy between 42.7 and 48 percent, with Landsman ahead by three to four points in each. Sixty-six days remain until the November 3 election.