The figures in the chart below are not actual results. They are estimates based on an Upshot/Siena College poll that showed Hillary Clinton and Donald J. Trump tied. Our estimate of the final vote, based on an Upshot/Siena College poll of North Carolina voters and what we know about the early vote Hillary Clinton Voted early Voting later Donald J. Trump Voted early Voting later

There aren’t many states more important this November than North Carolina, a rapidly changing state crucial to Donald J. Trump’s hopes of winning the White House and to Democrats’ hopes of winning the Senate. If Mr. Trump does not win the state, his path to the presidency, already narrow, becomes nearly impossible.

There also aren’t many states with better election data than North Carolina. The state releases detailed, individual-level information on every voter in the state. It even publishes a daily account of who has voted early, either in person or by mail.

To get a better sense of what’s going on, we’re trying an experiment: We’re estimating the result of the early vote and the Election Day vote by combining the rich data released by North Carolina with data from the Upshot/Siena survey of North Carolina.

The Upshot/Siena poll data drives these estimates. We’ve matched all 2,400 respondents from our three North Carolina surveys to the state’s voter data, and we’ve then estimated how every voter in the state of North Carolina is likely to vote.

In doing so, we’ve also untangled how voters have shifted over our three surveys, then estimated how they would vote today. The results, in other words, are drawn from data pooled from all three surveys, but reflect the race as it was in the weekend before the election, when our final poll showed a tied race

So far, here are our best estimates:

Already, about people have voted in North Carolina, out of about we think will eventually vote. Based on the voting history and demographic characteristics of those people, we think Hillary Clinton leads in North Carolina by about . We think she has an even larger lead – – among people who have already voted.

Here’s a breakdown of those estimates for the two major-party candidates:

In raw votes As a pct. Clinton Trump Clinton Trump Already voted Yet to vote Total estimates

Our polling data indicates that Mrs. Clinton has built a considerable lead in the early vote. The people who have turned out are even more supportive of her than one would guess from their demographic characteristics. But the voters who are left strongly support Mr. Trump. Whether enough of them turn out will decide the election.

These aren’t official results. They’re just estimates. If our polling is wrong, then our conclusions could be wrong as well.

Even if our polling is pretty good, there’s still uncertainty: Undecided voters and the supporters of Gary Johnson pose as much of a challenge for this project as they do for a typical survey. But by the end of the early vote, one of the biggest sources of uncertainty in polling – the composition of the electorate – will be greatly diminished.

The tight race represents a big shift from our earlier estimates. Those were based on our previous poll of North Carolina, which showed Mrs. Clinton ahead by seven points. The race has tightened since then, according to both our poll and other surveys of the state and nationwide.

The biggest factor is that Mr. Trump has made big gains among white and Republican-leaning voters over the last few weeks. The support of Gary Johnson has plummeted as well, falling to 3 percent from 8 percent in our last poll.

How many people have voted, and how many we think are yet to vote And how our estimates of the final vote have changed

These estimates have not shifted much because of the turnout. In general, the composition of the electorate has not meaningfully shifted in early voting.

Below, our estimates of the vote in North Carolina across different groups of voters.

By race

From the roughly early votes: Race Hillary Clinton Donald Trump White 70% of early voters 35% 62% Black 22% 95% 4% Hispanic 2% 76% 20% Other 6% 79% 19% From the roughly votes yet to be cast: Race Hillary Clinton Donald Trump White 72% of votes remaining 29% 65% Black 20% 90% 8% Hispanic 2% 60% 33% Other 6% 50% 45% Our best guess at the final vote in North Carolina: Race Hillary Clinton Donald Trump White 71% of all voters 33% 63% Black 21% 94% 5% Hispanic 2% 70% 25% Other 6% 69% 28%

At the start of early voting, we estimated that 71 percent of the final overall total of voters would be white and that 21.4 percent would be non-Hispanic black.

These pre-early-voting estimates were strictly based on vote history. A 45-year-old white person who voted only in 2012 and a 45-year-old black person who voted only in 2012 were given an equal chance of voting in our forecasting.

In practice, vote history isn’t the only factor that determines turnout. In recent elections, black voters in North Carolina have been likelier to vote than white voters with the same vote history. For this particular project, our estimates started out agnostic on whether black or white voters would turn out in greater numbers than their vote history suggests. The turnout should speak for itself.

If early voting had gone as it did in 2012, our estimate for the black share of the electorate would have gradually increased if infrequent and even previously unregistered black voters showed up in disproportionate numbers.

But black voters did not turn out anywhere near the same rate as they did in 2012. They represented 22 percent of early voters, down from 27 percent of the early vote in 2012.

As a result, our estimate for the eventual black share of the electorate has stayed steady at 21.4 percent. This would be a significantly smaller percentage than in 2012, when black voters represented 23 percent of the electorate.

By vote history

From the roughly early votes: Voted in 2014? Hillary Clinton Donald Trump Did not vote 43% of early voters 55% 42% Voted in 2014 57% 50% 49% From the roughly votes yet to be cast: Voted in 2014? Hillary Clinton Donald Trump Did not vote 46% of votes remaining 46% 46% Voted in 2014 54% 40% 56% Our best guess at the final vote in North Carolina: Voted in 2014? Hillary Clinton Donald Trump Did not vote 44% of all voters 52% 43% Voted in 2014 56% 47% 51%

Every vote counts, but not every vote tells us as much about who is winning the early vote.

There are some people who are all but sure to vote: They participate in just about every election. If they vote early, it doesn’t really change our view of the race. But if a voter whom we don’t expect to vote shows up, that moves the numbers. That’s what the campaigns are trying to do, too: They’re trying to get their less likely supporters to the polls.

One easy way to get a sense of whether infrequent voters are turning out is to look at whether they participated in the 2014 midterm election

We believe these voters will make up 44 percent of the electorate, and they support Mrs. Clinton by an eight-point margin.

By age

From the roughly early votes: Age group Hillary Clinton Donald Trump 18 to 29 13% of early voters 61% 35% 30 to 44 20% 56% 40% 45 to 64 39% 50% 48% 65 and older 27% 48% 51% From the roughly votes yet to be cast: Age group Hillary Clinton Donald Trump 18 to 29 18% of votes remaining 51% 40% 30 to 44 24% 44% 48% 45 to 64 37% 40% 56% 65 and older 20% 39% 58% Our best guess at the final vote in North Carolina: Age group Hillary Clinton Donald Trump 18 to 29 15% of all voters 57% 37% 30 to 44 21% 51% 43% 45 to 64 39% 47% 51% 65 and older 25% 45% 53%

Mrs. Clinton has a big lead among young voters, but our polling data suggests that the young voters who support her have been far likelier to vote early than those who oppose her.

Our model doesn’t suppose that trend will continue on Election Day. If it does, it could help her at the margins.

By party

From the roughly early votes: Party Hillary Clinton Donald Trump Democratic 42% of early voters 84% 14% Republican 32% 10% 88% Other 26% 51% 45% From the roughly votes yet to be cast: Party Hillary Clinton Donald Trump Democratic 37% of votes remaining 72% 24% Republican 33% 12% 82% Other 29% 40% 52% Our best guess at the final vote in North Carolina: Party Hillary Clinton Donald Trump Democratic 40% of all voters 80% 17% Republican 32% 11% 86% Other 27% 47% 48%

Democrats have a longstanding voter registration advantage in North Carolina, but a significant slice of them are conservative, older white Democrats who have been voting Republican in presidential elections.

There isn’t a realistic scenario in which registered Republicans would outnumber registered Democrats in the final count. That’s especially true in early voting, which is traditionally used more by Democrats than by Republicans.

In 2012, Democrats had an edge of 48 percent to 32 percent in party registration among early voters, and a 44-33 edge in the final count. Since then, the Democratic registration edge statewide has diminished, in large part as older conservatives have switched to the Republicans. At the same time, newly registered voters who support Democrats have been far likelier to register without affiliating with a party.

As a result, the expected Democratic registration edge is somewhat smaller than in the past: 40 percent to 32 percent for the Democrats.