Our Ohio Senate estimate moves 12.5 points toward Husted in a week

Our model now gives Sherrod Brown a 61 in 100 chance of winning the Ohio Senate special election against Republican incumbent Jon Husted. A week ago, in our run of September 16 at 10:02 AM ET, it gave him 74%. That is a move of 12.5 points of Democratic win probability toward Husted over seven days.

The mean margin in our simulations narrowed over the same span, from D+3.8 to D+1.6. The spread narrowed at the top and widened at the bottom: our 5th-to-95th percentile range ran from R+6.1 to D+13.6 last week and now runs from R+7.9 to D+11.2. That range still covers outcomes on both sides by several points, which is the model's way of saying it does not consider the race settled.

Nothing in the polling we hold accounts for the change. The only Ohio survey in the payload is a Trafalgar Group poll of 1,085 likely voters fielded September 14-16, which had Brown at 45.4% and Husted at 41.5%. That poll was already reflected in our estimate when we wrote about it on September 17, and no Ohio survey with a later field end has arrived since. So the movement is the model's, driven by inputs other than new state polling, and we are not going to assign it a cause the payload does not support. The estimate is back at the 61 in 100 it showed on September 14.

Nationally, our average of 30 generic-ballot polls over the past 45 days stands at D+8.1. Our model gives Democrats a 54% chance of Senate control, with a mean of 50.6 Democratic seats; 51 seats are needed for a Democratic majority, and 50 suffices for Republicans because the vice president is a Republican. Ohio is one of the seats that decides which side of that line the chamber lands on.