Democrats hold a 93% House chance as the Senate stays near even

Sixty-three days from the November 3 election, our model gives Democrats a 93 percent chance of winning a House majority and Republicans 6 percent. The mean Democratic seat count is 239.9, against the 218 seats needed for control. Our simulation draws correlated error at four levels — national, census division, state and individual district — but it has no term linking demographically similar districts in different places, because we have no cluster data to build one. That missing layer is our own gap, and it leaves the House control number marginally firmer than a fuller treatment would make it.

The Senate is close to even. Our model gives Democrats a 48 in 100 chance of a majority and Republicans 51 percent, with a mean of 50.2 Democratic seats. Democrats need 51 seats for control; Republicans need 50, because the vice president is a Republican and a 50-50 tie goes to them. That asymmetry is why the seat mean and the control probability point in slightly different directions.

Our generic ballot average stands at D+6.4, drawn from 26 polls over the past 45 days. Three of the most recent are consistent with it. An Ipsos survey for Reuters of 924 registered voters, fielded August 28-31, put Democrats at 43 percent and Republicans at 38. Morning Consult, polling 28,429 registered voters August 24-30, had Democrats at 47.1 and Republicans at 42.3. Quantus Insights, with 1,200 likely voters August 26-28, had Democrats at 49.7 and Republicans at 42.8.

Six races moved in the overnight run. OH-7 fell 24.8 points of Democratic win probability, from 56 percent to 31, the largest single shift on the board. Iowa's Senate race rose 17 points, from 23 percent to 40. Texas went from 53 percent to 68, and Michigan from 58 to 69. Two races moved the other way: New Hampshire's Senate seat dropped from 95 percent to 81, and Virginia's from 99 to 90.

Abacus Data released a set of Senate polls fielded August 26-28, each reported with a registered-voter sample and a smaller likely-voter subsample. In Iowa, the 500-voter registered sample had Josh Turek at 41 and Ashley Hinson at 36; the 323-voter likely sample had Turek 48, Hinson 41. In Ohio, Sherrod Brown led Jon Husted 40-33 among 500 registered voters and 46-41 among 306 likely voters. In Maine, Troy Jackson and Susan Collins were tied at 40 among 499 registered voters, while the 327-voter likely sample had Jackson 50, Collins 42. In South Carolina, Annie Andrews and the Republican were tied at 34 among 500 registered voters. Elsewhere in Iowa, a Wedgewood Polls survey of 600 likely voters, fielded August 27-29, had Hinson 50 and Turek 48 — a close race on those numbers. EPIC-MRA, polling 600 Michigan likely voters August 22-28, had Abdul El-Sayed at 47 and Mike Rogers at 43.