UNH poll shows Pappas up five, and our New Hampshire number eases to 91

A University of New Hampshire survey of 1,878 likely voters, fielded August 20-24, puts Democrat Chris Pappas at 45 percent and Republican Scott Brown at 40 percent in the race for New Hampshire's open Senate seat.

Our model now gives Pappas a 91 in 100 chance of winning the seat, with a mean margin of D+8.4 and a 5th-to-95th percentile range running from R+2.0 to D+18.8. That is a modest step down from the previous run this afternoon, which had him at 95 percent and a mean margin of D+10.8. The direction of the change comes from the poll itself: five points is a tighter result than the 12-point margin our site wrote about six days ago, and the average moved accordingly.

The substance of the race is unchanged. Pappas remains the clear favorite in our estimate, and the distribution still includes outcomes on both sides — the low end of our range has Brown winning by two. Neither candidate is an incumbent; the seat is held by Democrat Jeanne Shaheen.

Nationally, our model gives Democrats a 45 percent chance of Senate control and Republicans 55 percent, with a mean of 50.0 Democratic seats. Democrats need 51 seats for control and Republicans need 50, because the vice president is a Republican and a 50-50 tie goes to the Republicans. That arithmetic is why a race like New Hampshire carries weight even when one side is a strong favorite. In the House, our model gives Democrats a 93 percent chance of a majority, with a mean of 240.9 seats against the 218 needed; our simulation correlates error nationally, by census division, by state and by district, but has no term for demographically similar districts across state lines, so that House figure is marginally firmer than it should be. Our generic-ballot average stands at D+6.5 across 27 polls.