A clear conclusion from yesterday’s midterm elections was: Democrats have gained control of the House and Republicans expanded their majority in the US Senate.

For a more detailed understand of what this all might mean in terms of voter behavior in 2020 (after all, isn’t that why these midterms are being so closely watched?), exit polls are one of the few sources of information we have.

These surveys have their limitations because that they don’t do a good job representing all voting blocs equally but, for now, they are the most accurate data source available. Here are some of the key voter trends from Tuesday’s election:

Historically high turnout

So far, 98m votes have been counted. It will take days to reach a final total but Edison research estimates that 113m votes were cast in these midterms. That figure would translate to turnout of 49%, an enormous rise on the 2014 midterms where just 36.7% of eligible voters cast a ballot (historically, midterms experience much lower turnout than presidential elections).

Young voter surge – mainly for the Democrats

The younger the voter, the more likely they were to choose a Democratic party candidate for the House. A clear 68% of voters aged 18-24 chose the Democrats according to exit polls – a group that is credited with helping to boost the overall turnout figure.

It is interesting to observe age with other demographic traits like race. When looked at together, it becomes clear that the only older voters to choose the Republican party were white voters (non-white voters still chose the Democrats regardless of their age).

Race and gender

It’s possible to look at these two demographic groups in isolation (women voted Democrat, white people voted Republican) but to really understand voting patterns, it’s most helpful to look at race and gender together. CNN’s exit polls are useful here since they had a solid 18,778 respondents.

When combined, the only group to make a clear lean for the Republicans are white men, 60% of whom voted for the party. White women were split between the two parties while all other racial groups (regardless of gender) were majority Democrat.

Exit polling data on race and gender. Photograph: CNN

Key issues

No surprises that 88% of voters who approved of Donald Trump also chose the Republican party in these midterms, while 90% of those who disapproved of the president voted Democrat. Here are some other takeaways:

Respondents were asked which was a greater concern: illegitimate votes or that some might be prevented from voting. Seventy-eight percent of those who were concerned about voter fraud voted Republican in these midterms, while 80% of those who were worried about disenfranchisement voted Democrat. Note, there is no evidence whatsoever of widespread voter fraud while voter ID laws have prevented tens of thousands of voters in several states from exercising the franchise according to a report by the Government Accountability Office.

79% of those surveyed who said that “sexual harassment in this country today is not a serious problem” chose a Republican party candidate.

84% of those who said that “electing more women to public office” was not important chose the Republican party (more women won House seats in last night’s midterms than ever before, the vast majority of them were Democratic candidates).

87% of voters who said that “whites are favored in the US today” chose the Democratic party. In an almost precise mirroring, 85% of respondents who believed that “minorities are favored in the US today” chose the Republican party.

Late deciders

Most voters (three-quarters) made up their minds about who to vote for in the House election long ago but fascinatingly, 8% decided in the past week and an additional 8% said they reached their decision in the last few days. Those late deciders were slightly more likely to choose the Democrats over the Republicans.

Split suburbans

As in past elections, rural voters were slightly more inclined to vote Republican (56% said they had chosen the party in the midterms) while 65% of urban voters said they chose the Democratic party. But Americans who live in the suburbs were equally split between the two parties. That’s a key trend since Americans are more likely to live in the suburbs than anywhere else.

Are there any other voting trends you want me to take a look at here? Email me at mona.chalabi@theguardian.com