Ohio Senate estimate settles at 61 in 100 for Brown after a week of movement

Our model now gives Sherrod Brown, the Democrat, a 61 in 100 chance of winning the Ohio Senate special election against Republican Sen. Jon Husted. That is up 19.9 points from the 42% our September 7 run gave him, a move of seven days.

One poll of the race arrived in between. An InsiderAdvantage survey of 1,200 likely voters, fielded September 8-9, had Brown at 47.3% and Husted at 41.9%, a gap of 5.4 points. After that poll our published estimate stood at 70%; it has come down since to 61%, so the net change against the September 7 run is smaller than the swing at its widest point.

The expected margin moved with it. Our September 7 run had a mean margin of R+1.3; this one has D+1.8. The spread around that central estimate remains wide: our model's 5th-to-95th-percentile range runs from R+8.2 to D+11.7, which is to say it does not rule out a clear win for either candidate 50 days out. A 61% chance is close to three in five, not a result.

Nationally, our average of 23 generic-ballot polls taken over the past 45 days stands at D+6.9. Our model puts the Democratic chance of a Senate majority at 50% and the Republican chance at 49%, with a mean of 50.3 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. Ohio sits squarely inside that arithmetic: at a mean margin under two points, it is among the seats where our simulations most often diverge on which party reaches the threshold.