The Washington PostDemocracy Dies in Darkness

These 5 charts explain who voted how in the 2018 midterm election

House Minority Leader Nancy Pelosi (D-Calif.) speaks during a news conference Wednesday in Washington, a day after Democrats won control of the House. (Nicholas Kamm/AFP/Getty Images)

The 2018 midterm election dramatically shifted the balance of power in the House of Representatives, from Republican to Democratic control. Many expected that, given President Trump’s relatively low approval rating. Historically, that had meant the president’s party would lose many House races. Pre-election polling largely confirmed the likely Democratic takeover.

But here’s what we haven’t yet known: Which groups supported the Democrats in this election? How do these patterns compare to previous elections?

Below, you can see five charts that help to explain what happened. For the most part, these charts are based on data from the Cooperative Congressional Election Study (CCES), a large-scale academic survey conducted in every election year since 2008. For the 2018 CCES analysis, we used pre-election interviews with respondents weighted to be nationally representative of the adult population. We then applied a likely voter model trained on previous election cycles to create estimates for the 2018 electorate.

1. How did different age groups vote?

Majorities of millennials who intend to vote say they’ll support Democrats — except among white men

2. How did suburbanites vote?

3. As expected, women and men voted very differently

Another pattern everyone was watching was the gender gap — which, as the next chart shows, was the largest we have seen in at least a decade. While nearly 60 percent of women who voted for one of the two major parties voted for Democratic candidates, only 47 percent of men did. That’s a gender gap of 13 points.

4. Let’s break down women and men by race and education

But of course, women and men are incredibly broad groups, made up of every U.S. demographic. So which subgroups of women and men were furthest apart? The next chart plots the two-party vote share among white voters (since voters of color went overwhelmingly for Democratic candidates, no matter the gender), by gender and education.

Whites have fled the Democratic Party. Here’s how the nation got here.

5. Why did college-educated white women swing so far toward the Democrats?

What explains college-educated white women’s big shift? The final chart comes from analysis I conducted for Data for Progress. In that piece, I compare the role of voters’ attitudes about women in this election to the role it played in 2018.

Among other factors, I looked at what researchers call “hostile sexism,” a set of antagonistic attitudes toward women that stem from a belief that women want to control men. While hostile sexism was a strong predictor of support for Trump, it did not affect how people voted in their House races in 2016. That changed in 2018.

The chart below shows how higher levels of sexism are related to voting for the Republican candidate in both 2018 and 2016, controlling for other factors such as ideology, partisanship, racial attitudes and demographics. In 2016, a voter’s agreement or disagreement with sexist statements (which you can find on the x-axis) did not matter much for whether they voted for the Republican House candidate. In 2018, however, people who were more likely to disagree with sexist statements (i.e., had less hostile sexism) were much less likely to vote Republican.

Overall, these five charts suggest Republicans might wish to be concerned about being tied to a president whose rhetoric is often divisive and offensive. Doing so is turning off younger voters at historic rates, while also driving away women (especially those with college degrees). If the Republican Party brand becomes increasingly synonymous with Trump, these patterns may persist in 2020 and beyond.

Read more:

Brian F. Schaffner (@b_schaffner) is the Newhouse Professor of Civic Studies in Tisch College and the Department of Political Science at Tufts University.