538, an Independent pollster, conducted an aggregate of polls of Dem/GOP registered voters in the last 5 days. These polls ended at noon on 7/31 and don’t include voters' reactions and thoughts to DJT’s appearance at the NABJ. I selected a few of the questions I found interesting to share here.
Question 1 of 4: Do voters want Republicans or Democrats in Control of Congress?
Result: It's Evenly Divided with 45% of voters wanting Dems & 45% of voters wanting a GOP Congress. #Political
FiveThirtyEight is an aggregator, not a pollster. As far as I know, it does not do any polling itself.
Also, the data they do collect and aggregate is processed (like cheese) through their model. The results can be dicey at times (they predicted a blowout for Clinton and we know how that turned out).