A preliminary glance at exit polling data shows a stark racial divide – but the full picture is much more complicated, and offers clues to why polls were so badly off

Republican Donald Trump will become the next US president. Many will be wondering who, among the estimated 129 million voters in the 2016 election, Trump has to thank for his victory.

Possibly, not most of them. Current projections suggest that Democratic candidate Hillary Clinton might narrowly claim a larger share of the popular vote. But the distribution of votes in the electoral college still means that Trump finished the night with 276 of the 270 college votes needed to win – and, once final counts come in from states that still haven’t officially been called, that count will probably jump to 306.

As I have written, part of the reason Trump’s win is being described as a “stunning upset” is because most opinion polling was inaccurate. And yet, the only information we have right now to make sense of Trump’s victory is yet more polling data – this time from exit polls.

Those exit polls point to one clear, deep divide in voting behavior – race. White voters chose Trump, non-white voters chose Clinton. This appears to be different from previous polling data, where the difference between candidates’ national popularity was so narrow that relatively small errors could affect the overall accuracy of results. The gap in Trump support between white voters and non-white voters is so large that even if exit polls were inaccurate, that difference probably still stands.

Facebook Twitter Pinterest Exit polling data from election night. Photograph: NYT

Perhaps that’s not surprising for a candidate who was endorsed by the Ku Klux Klan. What’s more surprising though is that exit polling suggests Trump was able to slightly increase his vote share among black, Hispanic and Asian voters compared with Mitt Romney’s performance in 2012.

There are other demographic cleavages in US voting, but they don’t appear quite as dramatic as the racial one. Exit polls suggest that, as expected, more women voted for Clinton while more men voted for Donald Trump. Much like the UK’s Brexit result, younger voters (a demographic which typically has lower turnout rates) seemed to choose the losing candidate. Only 37% of voters aged 18-29 voted for Trump, compared with 53% of those aged 65 and over. Those numbers come from Edison Research, which spoke to 24,537 voters leaving 350 voting places across the country on election day.

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Exit polling data on income points to another surprising result. The poorest voters, those with an income of $49,000 or less, seemed to choose Clinton over Trump –albeit by a much smaller margin than in 2012. For months, Trump was projected to win big among this group.

All this doesn’t necessarily mean that the numbers were wrong. These exit polls don’t reflect how people, or demographics, really work. American voters are not poor or black or female or college educated. In reality, people fit into multiple different groups at once. Two facts are simultaneously possible – that the poorest voters chose Clinton and that the poorest white voters chose Trump.

In data analysis, this process of looking at two different variables at once means looking at the “crosstabs”. The exit polling data does offer us one such crosstab – race and educational status. Those numbers suggest that Trump has one very clear group supporting him: white voters who don’t have a college degree. The numbers on race and education point to such a clear cleavage that even if they are slightly inaccurate, the overall conclusion still likely holds true.

Facebook Twitter Pinterest Race and education: the dividing line. Photograph: NYT

That group might also offer some clues as to why polls were so badly off. Analysts have found that the states where Republican support was underestimated correlate with the states with a large non-college-educated white share of the population.

But it might be an overstatement to say that this group secured Trump’s victory. To understand that, we would need a detailed breakdown of votes by state, which we don’t yet have. There are other factors here, such as the millions of votes which went to third-party candidates, and whether Democratic turnout overall was down (it appears that it was).

Again, these numbers have their limitations – and they can be dangerous. Similar polling data led the Clinton campaign to feel quietly confident of a victory in Wisconsin and Michigan, and to therefore air few advertisements in those states. Both ended up voting for President-elect Donald Trump.