One poll narrows our AR-2 forecast, but Republicans stay favored

A Hendrix College survey of 1,112 likely voters in Arkansas' 2nd District, fielded August 12-13, put the Democratic candidate at 48% and the Republican at 44%. The poll is the only new number in this race, and it is closer than what our model had been carrying.

Our forecast moved accordingly. The Democrat's chance of winning the seat is now 34%, up from 21% in our previous run at 8:30 PM ET on August 20. Our mean margin narrowed from R+8.4 to R+4.3, and our 5th-to-95th percentile range now runs from R+21.4 to D+12.4, against R+25.3 to D+8.4 before. The Republican remains favored at 66%, so the direction of the race in our model has not changed — only the size of the expected margin and the width of the plausible outcomes.

One survey moving a district forecast by 13 percentage points is what happens when there is little else in the district to weigh it against. The Hendrix College poll did not report a margin of error in the data we have, and a four-point separation in a single sample is thin evidence for a lead. Our model treats it as one input alongside the national environment, where our average of 25 generic-ballot polls over the last 45 days stands at D+6.7.

Nationally, our model gives Democrats a 94 in 100 chance of winning House control, with a mean of 242.6 seats against the 218 needed. That figure carries a caveat of our own making: our simulation draws correlated error nationally, by census division, by state and by district, but we have no cluster data to correlate demographically similar districts across regions. Without it, the House control number is marginally firmer than a fuller accounting would leave it.