* The margin of error in both polls is 9 percentage points, however…

If sampling error were the only type of error in a poll, we would expect candidates who trail by one point in a poll of 512 people [533 in the Bost poll] to win about two out of every five races. But this probably understates the total error by a factor of two.

…Adding… I think this is true. I thought that claimed MoE was too high for polls of 500+ people. From comments…

More precisely, the MOE is +/- 4.7 for IL-6 and +/- 4.6 for IL-12. That actually is about right for a sample of ~500 voters.

* On to the polls. Republican US Rep. Peter Roskam leads Democrat Sean Casten 45-44 with 11 percent undecided. Republican US Rep. Mike Bost leads Democrat Brendan Kelly 44-43 with 13 percent undecided. Two-thirds of respondents in both surveys were reached on their mobile phones.

In Roskam’s suburban district, President Trump’s job approval rating is just 36 percent while 57 percent disapprove. The president is slightly above water in Bost’s rural/blue collar district 48-46.

51 percent in the Roskam poll said they preferred Democrats to take control of the US House, compared to 44 percent who wanted the GOP to stay in power. Those numbers went the other way in Bost’s district, with 46 picking the GOP and 43 choosing the Democrats.

* The Roskam poll is here. The Bost poll is here. Tell us what you think.