WASHINGTON (AP) — The New Hampshire primary and Nevada caucuses have passed, and South Carolina's vote is just days away — but there's still no winner of the Iowa caucuses.

Final results of the first contest to decide the Democratic Party's nominee to challenge President Donald Trump were released late Thursday, after the Iowa Democratic Party completed a recount of results at the request of two candidates, Bernie Sanders and Pete Buttigieg, who are essentially tied for the lead.

Following the initial delay in reporting results, and after observing irregularities in those results, The Associated Press has decided it will not declare a winner in Iowa.

For the AP to decide not to declare a result is unusual. Here are some answers to questions about the decision, the context in which it was made and what comes next:

___

WHAT'S BEHIND THE AP'S DECISION? AREN'T ALL THE RESULTS IN?

After the Iowa Democratic Party's release of recounted results on Thursday, Buttigieg leads Sanders by a margin of 0.04 percentage points.

That's in the count of what are known as state delegate equivalents, which is the outcome of a caucus that the AP uses to declare a winner. Buttigieg has about one more state delegate equivalent than does Sanders, out of 2,151 counted.

That follows a recount requested by Sanders and Buttigieg that reviewed and updated results in a small handful of precincts, out of more than 1,765 statewide.

The state party will vote to certify the results of the caucuses on Saturday. At that point, the caucuses will formally end, and no further changes to the results will be made.

The AP has reviewed the updated results and will not call a winner, given the remaining concerns about whether the overall results are fully accurate.

___

WHY ALL THIS TALK ABOUT DELEGATES? DIDN'T SANDERS WIN THE MOST VOTES?

Unlike a government-run primary election, with secret ballots cast at polling places, Iowa's Democratic caucuses are an event run by the Iowa Democratic Party. Iowans gather in high school gyms, public libraries and coffee shops and — in front of neighbors and friends, family and strangers — sort themselves into groups backing each of their party's candidates.

Until this year, the only results reported from that process was a tally of the number of state convention delegates — or "state delegate equivalents" — awarded to each candidate.

For the first time, the party in 2020 released three sets of results from its caucuses: adding the "first alignment" and "final alignment" of caucusgoers to the number of "state delegate equivalents" each candidate received.

During the caucuses, voters arriving at their caucus site filled out a card that listed their first choice; those results determined the "first alignment." Caucusgoers whose first-choice candidate failed to get at least 15% of the vote at their caucus site could switch support to a different candidate. After they had done so, the results were tabulated again to determine the caucus site's "final alignment."

Sanders does lead Buttigieg by 3.4 percentage points in the first alignment and 1.4 points on the second alignment.

But the AP has always declared the winner of the Iowa caucuses based on state delegate equivalents, which are calculated from the final alignment votes. That's because Democrats choose their overall nominee based on delegates.

While the first alignment and final alignment provide insight into the process, state delegate equivalents have the most direct bearing on the metric Democrats use to pick their nominee — delegates to the party's national convention.

___

SO WHO GETS THE MOST NATIONAL DELEGATES?

Iowa awards 41 national delegates in its caucuses. As it stands, Buttigieg has 13 and Sanders has 12. Trailing are Elizabeth Warren with eight, Joe Biden with six and Amy Klobuchar with one.

The 41st and final delegate from Iowa will go to the overall winner. The AP will update its tally of the national delegates won in Iowa with that final delegate on Saturday, once the Iowa Democratic Party formally votes to certify the results of its caucuses.

___

SO WHAT HAPPENED WITH THE COUNT? AREN'T ELECTION CONTROLS IN PLACE?

The reporting of caucus results in Iowa this year was marred by multiple problems: tech issues with the mobile phone app used to collect data from caucus sites, an overwhelming number of calls to the party's backup phone system and a subsequent delay of several days in reporting the results.

An AP review of initial results provided by the Iowa Democratic Party also found numerous precinct results that contained errors or were inconsistent with party rules. For example, dozens of precincts reported more final alignment votes than first alignment votes, which is not possible under party rules.

In some other precincts, candidates won state delegate equivalents even though officials recorded them as receiving no votes in the final alignment.

Iowa party officials said there are reasons for the discrepancies that would not have changed the number of state delegate equivalents awarded to each candidate. But they didn't confirm the cause of discrepancies in individual precincts.

There were also a handful of precincts in which officials awarded more state delegate equivalents to candidates than there were available to be won.

Under party rules, the Sanders and Buttigieg campaigns could first request a recanvass, which they did. A recanvass is not a recount, but a check of the vote count to ensure the results were added correctly. Once that process was complete, they requested the recount the state party completed on Thursday.

However, the two campaigns did not request a statewide recanvass and recount. Instead, they asked the party to look at a select number of precincts in which they felt an error would benefit their candidate.

That means other locations where errors appeared to have occurred remain unexamined — and unchanged.

___

HAS THE AP NOT CALLED A RACE BEFORE?

Yes, though it is rare. When it does happen, it's usually because a very close race is headed for a recanvass or a recount.

The most notable example was in 2000, when the results of the race between George W. Bush and Al Gore were too close to call at the end of election night. The AP decided not to call the race for either candidate. The ensuing recount dispute eventually reached the Supreme Court, which effectively cleared the way for Bush to become president.

Last year, the AP declared the election for Kentucky governor as "too close to call" when the election night count ended with Republican incumbent Matt Bevin behind by 5,000 votes out of more than 1.4 million cast. Bevin requested a recanvass of the results, and the AP only called the race after he conceded to now-Gov. Andy Beshear, a Democrat.

The AP does its data-driven race calls every year with the utmost care. With an extensive vote-counting apparatus across the nation, the AP calls close to 7,000 races in a presidential election year. Its race calls are used by media on both sides of the political spectrum and have been regarded for years as highly reliable.

___

Catch up on the 2020 election campaign with AP experts on our weekly politics podcast, "Ground Game."