Here is a snapshot of eight predictions for the outcomes of the House elections this year.
Political scientists James Campbell, Michael Lewis-Beck, and Charles Tien provide the most optimistic predictions for the Republicans with forecasts of 249 or 250 seats. All the other forecasters see more modest gains for the Republicans with the number of predicted seats between 239 and 244. Overall across the eight estimates the mean (and median) forecast is for the Republicans to end up with 243 seats, for a gain of nine from their 2012 total. In addition, the folks at Real Clear Politics, the Cook Political Report, and the Rothenberg Political Report also see the outcome in a similar fashion, with predictions ranging from the low to mid 240’s for the Republicans.
Virtually all the forecasters provide “point estimates” of the outcomes along with confidence intervals, which take into account various types of uncertainty. At Election Lab we do this by repeatedly simulating the 435 House elections to produce a distribution of predicted outcomes. In our most recent set of simulations the Republicans won a majority in every simulation and picked up seats in 97 percent of them. And, in 8 percent of the simulations they won at least 250 seats. Here is the distribution of the 1,000 simulated outcomes.
In light of the variability in the estimates produced by the uncertainty, we do not expect to nail the outcome exactly. At the same time, we don’t expect to be very far off. Fully 90 percent of the simulations produce Republican seat totals between 236 and 251.
The explanation for the sunny Republican prospects is straightforward and explained by John yesterday. Simply put, because the president is a Democrat, the midterm penalty helps the Republicans. And, on top of that, the president’s approval ratings have been significantly below average for midterm election cycles. As I mentioned a couple of weeks ago, a good Republican year has been in the cards for awhile. As the votes come in on Election Day, we will be surprised if that prediction does not come to pass.