If Democrats were hoping for a late surge to improve their chances of retaining control of the House, there isn’t any evidence of it yet. Instead, Republicans have generally had the better of the polls in individual House districts released in the past 24 hours.

FiveThirtyEight’s forecast now projects the most likely composition of the House to be 231 Republicans and 204 Democrats. This is a one-seat improvement for the Republicans from yesterday’s forecast, and would mean that they’d gain a net of 52 seats over all.

There is uncertainty in the forecast: Democrats have a 20 percent chance of maintaining control of the House, essentially unchanged from a 21 percent chance yesterday. Much of this 20 percent probability reflects the potential for there to be systematic errors in the polling, as there were in years like 1998.

Since there are a very large number of competitive seats, relatively small anomalies in the polling could potentially affect the outcome of dozens of races. Although the Democrats’ overall position is poor, it is not yet so poor that it couldn’t be salvaged if they beat their polling averages by 2 or 3 points nationwide.

Still, such errors could also work in Republicans’ favor, potentially enabling gains in excess of 60 or even 70 seats. And much of the data released within the last day suggests that, if anything, they are strengthening their position. Republican candidates received encouraging polling numbers today in districts like the California 20th, the New York 20th, the Florida Eighth, the New Jersey Third, the Virginia Ninth, and the Idaho First, and their winning chances there were improved as a result.

Democrats did see a few relatively strong polls today, like in the Maryland First District and the Pennsylvania 10th. I’d caution against the notion that the “bottom is falling out” for Democrats, particularly given that their polling in Senate and governors’ races has been reasonably strong in the past several days, and since generic ballot polls show flat trends.

The upside case for Republicans, however, remains very high. And one gets the sense that the extremely large playing field in the House is doing more to stretch Democratic resources than Republican ones, particularly given that Republicans have sometimes been able to rely on fund-raising from outside groups to get a second wind in marginally competitive districts that they might otherwise have had to give up on. If pressed, I’d probably bet on the Republican side of the 52-seat over-under line that our model sets today.