This article was co-written by Dominic Skinnion, who forecasted the Senate races, and Lucy Ding, who forecasted the House races.
Overview
Democrats currently control both the Senate and the House by slim margins. The Senate stands at a 50-50 split, with Vice President Kamala Harris casting the deciding vote for Democrats if necessary. In the House of Representatives, Democrats also hold 220 of the 435 seats, only eight more than the Republicans’ 212. As is common in midterm elections, the incumbent president’s party is expected to lose seats. With just a couple days left until voters cast their ballots, Republicans hope to see gains in both the House and the Senate and are eager to take control of both chambers. According to the Washington Post, open-seat retirements, a troubling economy, and redistricting all point in favor of Republicans gaining seats in the midterm election.
House & Senate Forecast
Our forecast predicts that Republicans will control the House with 219 seats, compared to the Democrats’ 216 seats. Republicans are predicted to gain seven seats, while Democrats are predicted to lose four; the three seat discrepancy results from the House having three current vacant seats.
Our forecast also predicts that Republicans will control the Senate with 51 seats, compared to the Democrats’ 49 seats. In our simulations of the races, Republicans controlled the Senate 53.2% of the time, meaning that control of the Senate is nearly equivalent to the odds of a coin toss. Our model predicts that Republicans will flip both Georgia and Nevada, whereas Democrats will flip Pennsylvania.
Georgia
In 2020, both of Georgia’s two Republican Senators suffered defeats in a runoff election to their Democratic challengers. Reverend Raphael Warnock defeated Sen. Kelly Loeffler, who had been appointed to the Senate just a year earlier. Of the nearly 4.5 million votes cast in the election, Warnock defeated Loeffler with 51% of the vote. As Loeffler was initially appointed to fill a vacancy left by the resignation of former Sen. Johnny Isakson whose term was set to expire in 2023, Georgia voters must again cast their ballots for the Senate. Herschel Walker, who won the Heisman in 1982 as a legendary running back for the University of Georgia, is the Republican nominee for the 2022 Georgia Senate race to face off against incumbent Raphael Warnock. Walker is among a wave of famous figures to run for a seat in the Senate; fellow Republican nominees include JD Vance, famed author of Hillbilly Elegy, in Ohio and Dr. Mehmet Oz, known for his talk show, in Pennsylvania. Due to the narrow victory for Warnock in 2020, this election is one of the most closely watched races for Republicans to potentially take back a majority in the Senate.
Voters in Georgia cite the economy, abortion, and gun control as key issues that will shape the election. Warnock’s campaign acknowledges the rising costs seen across the country and in Georgia, and he highlights his goals to suspend the federal gas tax and to fight supply chain issues. During the October debate, Walker directly blamed President Biden for rising inflation, and he placed an emphasis on American energy independence to fight high gas prices. In addition, Warnock voted in favor of the bipartisan legislation that enacted gun control reforms in the wake of the Uvalde shooting. Walker’s campaign has called these efforts infringements on the Second Amendment. But perhaps the most publicized aspect of the race is the candidates’ views on abortion. Warnock calls himself a “pro-choice pastor” who believes that the Supreme Court’s overturning of Roe v. Wade was a failure for women’s rights. Walker, on the other hand, had previously supported a federal ban on abortion without exception, though during the debate said that he supports Georgia’s statewide ban after cardiac activity is detected. However, Walker has come under fire for his views on abortion after two women have come forward alleging that he had paid for their abortions.
While Warnock had been leading in the polls for the last four months, FiveThirtyEight’s latest polls now show the candidates as evenly tied, with less than a week until the election. Using our polls-based model, we forecast that Walker will win the election with a two-party vote share of 50.6%. In our simulations of the election, Walker won 56.5% of the time, a very close toss-up.
Pennsylvania
In late 2020, Pennsylvania Sen. Pat Toomey announced that he would not seek reelection. While the Senate seat is held by Republicans, Pennsylvania is known as a battleground state; its other senator is Bob Casey, a Democrat, and the state voted narrowly for Donald Trump in 2016 by less than 1% and for Joe Biden in 2020 by just over 1%. This race stands as a potential gain for Democrats. Current Lt. Gov. John Fetterman is the Democratic nominee and Dr. Mehmet Oz, known for his eponymous television show, is the Republican nominee.
While political issues such as crime and abortion have taken center stage, this race is also about the candidates themselves. Fetterman suffered a stroke nearly half a year ago and, as evidenced by his performance in the late October debate, is still enduring the effects. Republicans have questioned whether Fetterman is fit to serve in office given his medical condition. On the other hand, Democrats have raised concerns about Oz’s residency, hoping to distance the Republican nominee from Pennsylvania voters. Of the issues highlighted during the October debate, crime was the one of greatest focus for Oz, with the candidate painting himself as more tough-on-crime than his opponent. Fetterman fended off such attacks, pointing to his record of low gun violence as mayor of Braddock. On the topic of abortion, Oz said he supports leaving the decision up to states, reflecting the Supreme Court decision in Dobbs, whereas Fetterman pointed to Roe as his preferred framework.
According to FiveThirtyEight’s latest polls, Fetterman’s 5% lead in polling shrank in the last month, and the platform now classifies the race as even. Our polls-based model predicts that Fetterman will win the election with a two-party vote share of 52.7%. In our simulations of the election, Fetterman won the race 78.8% of the time.
Nevada
In both 2016 and 2020, Donald Trump lost Nevada by about 2.5%, and Joe Biden performed slightly worse than Hillary Clinton. While the Senate seat is currently held by Catherine Cortez Masto, a Democrat, recent polling shows her narrowly trailing Republican challenger Adam Laxalt. Cortez Masto has served one term in the Senate and became the first Latina in the chamber when she took office in 2018, winning by a slim 2.4% margin of victory. Laxalt formerly ran for governor of Nevada in 2018, losing the election to Steve Sisolak by 4%. If history is any indication of the upcoming election, it would seem that Cortez Masto has the upperhand. However, both parties know that the fate of the Senate could hinge on this election, and have poured hundreds of millions of dollars into the race as a result.
As reported by the New York Times, the race pits views on abortion against those on the economy. Laxalt is strongly pro-life and vows to vote against Democratic proposals regarding abortion. On the other hand, Cortez Masto has argued against Republicans’ attempts to legislate a federal abortion ban, pointing to the fact that Nevadans voted to enshrine abortion into state law. However, as is the case in many of these close Senate races, Republicans are hoping to capitalize on inflation as an indicator that President Biden and the Democrats cannot be trusted with the economy. The Laxalt campaign considers rising costs to amount to a “massive tax increase” and aims to stop the “spending spree” in Washington.
According to FiveThirtyEight’s latest polls, Laxalt now holds a 1% lead in polling over Cortez Masto. Our polls-based model predicts that Laxalt will win the election with a two-party vote share of 51.7%. Additionally, in our simulations, Laxalt won the election 65.8% of the time.
Additional Races
For additional races, our model predictions and simulation results are below.
Ohio: Vance (R) wins with a two-party vote share of 50.6%. (Vance wins in 57.4% of the simulations).
New Hampshire: Hassan (D) wins with a two-party vote share of 51.4%. (Hassan wins in 63.4% of the simulations).
Washington: Murray (D) wins with a two-party vote share of 51.9%. (Murray wins in 67.4% of the simulations).
Wisconsin: Johnson (R) wins with a two-party vote share of 51.96%. (Johnson wins in 69.4% of the simulations).
North Carolina: Budd (R) wins with a two-party vote share of 52.3%. (Budd wins in 75.0% of the simulations).
Arizona: Kelly (D) wins with a two-party vote share of 52.5%. (Kelly wins in 75.6% of the simulations).
Colorado: Bennet (D) wins with a two-party vote share of 52.7%. (Bennet wins in 77.5% of the simulations).
Methods
For our Senate forecast, we used data from FiveThirtyEight, including historical Senate polls from 2018 and 2020, current Senate polls from 2022, and Senate election results. In our univariate linear model, we used a weighted running average of the Democratic two-party polling percent to predict the election result using the 2018 and 2020 data. The running average was weighted by sample size and inversely weighted by days until the election. Using this model and current polls, we predicted the outcomes of the current Senate races. Because our model also provides uncertainty estimates, we conducted simulations of the elections as well.
For our House forecast, we used nationwide generic ballot averages from FiveThirtyEight with polls going back to 2010 and current polls from 2022. We also used previous election results recombined to take into account redistricting from Dave’s Redistricting, redistricting data from the Harvard ALARM project, expert predictions from the Cook Political Report, Inside Elections, and Sabato’s Crystal Ball, and GDP data. Our ensemble model consists of a pooled linear regression of our fundamental variables across all districts and an average of the Democratic lean of the district in the last three elections calculated by recombining the past Democratic vote in the precincts that fall into the new districts.
Note that the model predictions are subject to change given the release of new polls.
