DavidMRothschild on November 01, 2014 @ 12:34PM
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.
The forecasts are generated with two type of data: fundamental data and the Cook Reports. The fundamental model is very simple: past election results, changes in demographics, and incumbent running. The Cook Reports adds a subjective value that they update every few days. I simply took this data, put it into a probit regression from previous years, and used the coefficients to project for 2014.
What I am going to be following closely on Election Day, besides the exact number of seats, is the national population vote. The Republicans are poised to get a much lower percentage than they did in 2010, just higher than they did in 2012.
Starting 2016 we hope to use district-by-district polling, but until then, this should give a pretty strong prediction for Election Day 2014.
DavidMRothschild on October 31, 2014 @ 12:51PM
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.
The remaining states: Kansas, Georgia, Iowa, and Alaska, are all very tight. Kansas has a wildcard situation in both, leading candidate, by the slimmest of margins, is an independent. Further, the incumbent Republican governor is losing. So, people may vote differently than the polls if they panic about giving the Democrats too big of victory or where Orman, the independent will caucus. Georgia is also tough for the Democrats, because Nunn does not have enough to win without a runoff and a runoff lowers her likelihood of victory. Iowa is the only one of the four where the uncertainty is still a lot about the campaign, not Election Day. The Republican is a bit of wild card and has been stumbling down the stretch, avoiding spontaneous appearance sand interviews, trying “run out the clock.” Somehow Begich, the incumbent Democratic senator in Alaska, keeps the race close and everything comes down to whether he truly make a huge turnout on Election Day that overcomes challenger Sullivan’s slight lead in the polls.
Here is New York Times and FiveThirtyEight compared with PredictWise. FiveThirtyEight is surprisingly bullish on the Democrats in Kentucky.
DavidMRothschild on October 28, 2014 @ 6:52PM
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.
Iowa is back in play, as the next most likely to flip. This is not surprising as the Republican Ernst is a wildcard. She was my pre-season pick for an embarrassing and costly gaff. Alaska has had some crazy polls recently, but any poll with Don Young only up by 1 point is pretty suspect (despite his recent erratic behavior). The Democratic incumbent Begich is still in a lot of trouble holding his seat.
Here is New York Times and FiveThirtyEight compared with PredictWise.
The crazy thing is that as these states go up and down there is not that much movement in the likely outcome. There has been a steady 22% or so with 48 seats for the Democrats as the most likely outcome. But, the likelihood of the Democrats controlling the senate has fallen as 49 or 50 seats have fallen and 47 seats has risen.
DavidMRothschild on October 27, 2014 @ 9:02PM
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. (For more background, you can read the paper or this Q&A with Justin in 2012.)
When it comes to the 2014 senatorial elections the most interesting differentials between the expectation polling with traditional intention polling is the sizable lead in the expectation polling for the Republican incumbent Roberts in Kansas and Republican Perdue in the open Georgia seat. Both of these are dead-heats with the litany of quantitative forecasters (Upshot, FiveThirtyEight, Huffington Posts’ Pollster, etc.) whose forecasts are mainly driven from traditional polling. And, the traditional intention question in this YouGov poll also has them within the margin of error. But, the Republicans have commanding leads in the expectation question.
The below chart shows the percent of Democratic and Republican supporters that expect the candidate from the other party to win the election. I count just the supporters that expected one of the two major candidates to win the election (i.e., I disregard those people who respond that they do not know who will win). I plotted them from left to right depending on the expected vote share of the Republican candidate on PredictWise.
Note: there is no Democratic candidate in Kansas, but rather an independent running against a Republican.
Despite millions of dollars of polls (each poll in Pollster and Real Clear Politics’ lists costs tens of thousands of dollars) and millions of lines of historical data feeding into PredictWise’s algorithms, this single poll’s expectation polling breaks perfectly on the 50% line. For every election that PredictWise expects the Republican to win, a higher percentage of Democrats cross over to the Republican candidate. Similarly, for every election that PredictWise expects the Democrat to win, a higher percentage of Republicans cross over to the Democratic candidate.
There is strong upward slope depending on how convincing PredictWise expects the election to be, but all of the identification comes from the opposite party support. The percentage of Republicans that expect the Republican candidate to win is not too interesting once the Republican has a commanding lead (right side of the chart). But, the left side of the chart has a lot of identification about the expected vote share. While it is not a strictly monotonic relationship, generally, the higher percentage of the vote share the Democratic candidate is likely to receive, the more Republicans cross over and think the Democratic candidate will win.
We know that there is a lot of information going into people’s expectations: their own voting intention, the voting intention of their social network, and what they are hearing from the media. Further, this interplay of information varies by demographics. Yet, what matters for forecasting is not the exact information that goes into each forecast, but that it is meaningful information and that its relationship with the outcome is stable.
The data from expectation polling is so powerful, that it is the equivalent of the respondent going out and asking 10 random likely voters who they will vote for, including their own vote, and then telling the pollster who won his/her private poll (of 10 random likely voters and themselves). We do not think that that actually is what people do when they answer the poll, but that is how powerful the poll is for forecasting.
We have no problem that 30-50 percent of partisans think their candidate is going to win in landslide losses; actually it makes perfect sense! In our model that percentage perfectly mirrors the impact of the supporter including him/herself in their poll. A Republican supporter starts his/her personal poll with one definite Republican supporter. We know in reality it is also driven by some wishful thinking, but that is ok, because, this relationship between expectations and outcomes is stable through dozens of election cycles, with varying degrees of media coverage.
So, PredictWise, with its millions of dollars of inputs and millions of lines of data is saying a toss-up in Georgia and Kansas. But, the expectation of the local voters, from just one poll, is a mighty powerful data point. Thus, I expect Georgia and Kansas will likely go Republican.
DavidMRothschild on October 23, 2014 @ 4:02PM
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).
Second, Colorado, a blue state, is proving very difficult for the Democrats in the polls; both the senatorial and gubernatorial incumbents are losing. I do not have a great explanation for this, but it is consistent in both races. I have heard arguments on both sides and feel confident in saying it is equally likely the polls are off in either direction; there is no reason, ex-ante, to assume the polls are off in the direction of the Republicans.
Third, Iowa is still a wild card in that it is both very tight and Ernst is very conservative and her handlers appear worried about her talking unscripted. A few hours ago she skipped her planned meeting the editorial board of the largest paper in Iowa. The 27% in Iowa reflects the uncertainty in the polls, there is slightly additional uncertainty in the candidate that the model is not capable of fully realizing.
Here is New York Times and FiveThirtyEight compared with PredictWise: