Q&A: How and why AP called Clinton-Sanders race when it did

WASHINGTON – The question burned late into the night: Who won the Iowa Democratic presidential caucuses, Hillary Clinton or Bernie Sanders? There would be no answer until well into the next day.

News organizations widely rely on The Associated Press to call the winner in elections and, in presidential caucuses and primaries, to determine the number of delegates won by candidates to the nominating conventions. On Monday night, a close approximation of the delegates won by Clinton and Sanders was known. But the winner wasn’t – not until early Tuesday afternoon.

Some questions and answers about how the AP determined that Clinton won Iowa and how it allocated delegates in the Democratic contest:

Q: Why didn’t the AP call the winner in the Iowa Democratic caucuses on Monday night?

A: The race was too close. Clinton’s margin over Sanders was so minuscule that it risked being erased if vote-counting errors were discovered later.

The AP uses data from three sources to call races. First, entrance or exit polls of voters arriving to caucuses or leaving voting precincts (on Monday, entrance polls were used). Second, an analysis of actual votes from a random sample of precincts across each state. Third, the AP vote count, which tabulates all actual votes as they are reported from precincts to counties, or towns or parishes.

For the very closest races, the AP depends heavily on actual vote returns, as they slowly or rapidly flow in depending on circumstances, to make a call.

Q: What changed on Tuesday afternoon that led the AP to call the race for Clinton?

A: Three factors enabled the AP to call the race for Clinton just after 1 p.m. EST: All the results had been tallied, the Iowa Democratic Party told the AP it would not conduct a recount of any results, and the Sanders campaign said it was not interested in challenging any results.

Clinton in the end won by less than three-tenths of 1 percent.

Q: If Clinton won the caucuses, why didn’t she get all the delegates?

A: It’s not winner take all.

Iowa Democrats award delegates proportionally, based on the statewide vote and the vote in individual congressional districts. Clinton won two more delegates than Sanders – the tally was 23-21 – even though the vote was very close to a tie. That is because she got the most votes in one congressional district. Seven delegates were at stake in the Third District; she won 4, he won 3.

Also, a pot of 9 delegates was awarded based on the statewide vote. By narrowly winning the statewide vote, Clinton got 5 and Sanders got 4.

Q: So, what’s the delegate count heading into New Hampshire?

A: Clinton has a big lead, thanks to the party establishment.

Party officials known as superdelegates can support the candidate of their choice. When superdelegates are counted, Clinton has a total of 385 delegates and Sanders only has 29. More than half of the party’s superdelegates have decided whom to support – though they can always change their minds.

It takes 2,382 delegates to win the Democratic nomination for president.

Q: Since delegates determine who wins the nomination, and Sanders and Clinton split them almost equally, why does it matter who got the most votes in Iowa?

A: Politics craves a voting winner. In real time, momentum is shaped by which candidate wins the most votes, and that’s how history will remember Iowa in 2016.

In truth, Iowa’s delegate allotment is tiny compared with those of the big states to come.

Associated Press writers David Pace, who directs the AP’s race-calling efforts, and Stephen Ohlemacher, who runs the AP’s delegate count, contributed to this report.