InsiderAdvantage finds Michigan Senate race close; our forecast stays at 66 percent

An InsiderAdvantage survey of 1,200 likely voters in Michigan, fielded September 16-17, put Democrat Abdul El-Sayed at 46.6 percent and Republican Mike Rogers at 44.7 percent, with 1.1 percent for other candidates. That gap is narrow enough that the race is best described as close rather than as a lead for either candidate.

Our forecast did not move on it. The model gives El-Sayed a 66 in 100 chance of winning the seat, with a mean margin of D+2.5 and a 5th-to-95th percentile range from R+7.3 to D+12.2. The previous run, at 8:32 AM ET on September 18, had the same 66 percent, a mean margin of D+2.4 and a range of R+7.4 to D+12.1. The new poll sits close to where our average of this race already was, so it confirmed the existing picture rather than changing it.

This is an open seat. Democrat Gary Peters holds it now and is not on the ballot; El-Sayed and Rogers are the candidates. Forty-six days remain until the November 3 election.

Nationally, our average of 28 generic-ballot polls over the past 45 days stands at D+7.4. Our Senate model gives Democrats a 52 in 100 chance of winning control and Republicans 47 percent, with a mean of 50.5 Democratic seats. Democrats need 51 seats for control and Republicans 50, because the vice president is a Republican and a 50-50 tie goes to the Republicans. That margin is thin enough that a state polling within two points, as Michigan does here, carries real weight in the chamber outcome. In the House, our model puts the Democratic chance of a majority at 97 percent, with a mean of 243.1 seats against the 218 needed. One caution on that figure is ours: our simulation correlates error nationally, by census division, by state and by district, but has no term linking demographically similar districts in different places, so the House control number is marginally firmer than a fuller model would make it.