Republicans at about 85% to capture U.S. Senate

The Republicans are about 85% likely to take control of the U.S. Senate in January, 2015. This is going to happen, because the Democrats are going to win Blue States and the Republicans are going to win Red States. And, the Republicans are likely going to win two crucial Purple States (Iowa and Colorado). This election is not wave or a disaster for either party, but pretty much as should be expected. The most likely outcome is going to be the Democrats controlling 47-8 seats to the Republican 52-3.

The Democratic path to victory is very simple; they need to capture both New Hampshire and North Carolina, which are likely, and then three additional states of the five in play. The runoff system makes it very unlikely they will win in Georgie and Louisiana. And, I do not think Kansas’ Orman is going to make himself the swing vote with a 49 Democratic senate. Why would he do that if he can switch back in 2017 with seniority when the Democrats recapture the senate?

Hidden Errors and Overconfident Pollsters

Written with Sharad Goel and Houshmand Shirani-Mehr

Election forecasts, whether on HuffingtonPost's Pollster, New York Times’ Upshot, FiveThirtyEight, or PredictWise, report a margin of error of typically 3 percentage points. That means that 95% of the time the election outcome should lie within that interval. We find, however, that the true error is actually much larger than that, and moreover, polls historically understate support for Democratic candidates.

Election Update – 11/2, 2 Days

The Democrats are likely to lose the senate for two years. My predictions have been consistently more bullish on Republican victory than any of the other main forecasters: New York Times’ Upshot, FiveThirtyEight, HuffingtonPost’s Pollster, Princeton’s Sam Wang, etc. And, to be frank, the data is more generous to the Democrats than my gut, but I am obliged to run with the data.

The Democrats will have 47 seats if they take all of their certain races, along with New Hampshire and North Carolina. Of course, New Hampshire and North Carolina are not certain, but for the sake of this exercise, let us assume the Democrats take those seats. There are just eight other seats that are even remotely in play, and the Democrats would have to win three of them to get to a 50/50 tie, where Joe Biden is the tie-breaker.

Republicans are going to win the U.S. House

The Republicans are going to hold on to the House. Our latest forecast has the Republicans controlling 237 seats to 198 seats for the Democrats following this election. After the 2012 election the Republicans controlled 234 seats to 201 seats; we are projecting a gain of 3 seats. In the 2012 election the Democrats receive 59.6 million to 58.2 million votes for 50.6% of the two-party vote. Currently Huffington Post’s Pollster and Real Clear Politics have the national popular House vote at between 1.5 and 2.5 percentage points for the Republicans.

Election Update – 10/31, 4 Days

As we near Election Day there are really 8 competitive elections out of 36. This is normal compared with previous years. If we assume that the other 28 elections are now done, the Republicans are going to go into Election Night with 47 seats and the Democrats with 45 seats. If you want to expand he realm of possibility to anything that is not 0% and 100% (assuming the Republicans have not already taken Arkansas and Kentucky), then there are 10 seats in play and the chamber is 45 to 45.

The Democrats are heavily favored in two elections: New Hampshire and North Carolina; the Republicans are heavily favored in Louisiana and Colorado. Colorado is the most interesting of these four states, as their new voting scheme could mess up the polling. Early voting does look ok for Democrats in Colorado, but it needs to be great.

Election Update – 10/28, 7 Days

The Democrats have had a few good days in the polls, but it is unlikely to be enough to hold onto the senate. Currently the Democrats are about 25% to hold the senate, up from a low of 20% yesterday.

Despite a crazy outlier poll today, Shaheen looks more and more likely to old in New Hampshire against former Massachusetts’ senator Brown. And, Hagan is holding the lead in North Carolina for another week against challenger Tillis. But, the reason it has been a good week for the Democrats is that there were so few races left in their column after last week!

Both Georgia and Kansas have stayed really tight. Georgia is increasingly likely to go to runoff where, despite the current polling, the Democratic candidate, Nunn, will be in trouble. As turnout decreases the Democratic candidates lose voters.

Expectation question as a poll of polls

The New York Times’ Upshot published an article on their latest New York Times/CBS News/ YouGov poll which highlighted work that I have done with Justin Wolfers of the University of Michigan on expectation polling. The expectation question asks, “Regardless of how you are voting, which candidate do you think is most likely to be elected?” Historically, this question has been extremely effective at pointing towards the eventual winner of the election and, even identifying the vote share.

Election Update – 10/23, 12 Days

Things just keep getting worse for the Democrats in the senate. We now have the Democrats at just 19% to hold onto the senate. The amazing thing is that the continuous slide is not any serious slip-ups, but just the gradual shifting of leaning Republican to strong Republicans and one (or two) big surprises.

First, it was never really likely that the Democrats were going to carry Georgia, Alaska, Louisiana, South Dakota, Kentucky, or Arkansas. Several of the seats were blue, but the states are red. Over the last few months anything thing should be red, has just gotten a little redder, and that cements as time goes by. It is nearly Election Day and there have been no campaign altering incidents (i.e., no talk of rape, like Mourdock in 2012, or macaca, like George Allen in 2006).

Election Update – 10/19, 16 Days

The last week and a half has been an unmitigated disaster for the Democrats in the polls and their fleeting chances of holding onto the majority of the senate.

The Democrats only bright spot has been Georgia, where Michelle Nunn has pushed into a tight race with David Perdue. The most likely outcome of the election is a runoff between the two candidates, as it is likely neither will get 50% of the vote. Which is why, despite leading many polls, Nunn is still slightly less than 50% to win, as Libertarian supporters are little more likely to break for Perdue in a runoff.

The biggest movement is in Kansas, where voters appear to be second guessing their choice of a Democratic leaning independent. The next biggest movement is more surprising, as the incumbent Democratic senator Udall in CO has fallen steadily behind the Republican challenger Gardner. Finally, the Iowa senate race has been a bit more of a regular roller coaster as Ernst, the Republican, holds a slight, but steady, lead over Braley.