The real reason it's going to take a while to know who won in some midterm races

Stephen Richer no longer runs elections in the fourth-largest county in the country.But for the rest of his life, he'll remember the feeling when polls closed on an election night.More than a million ballots staring at him and his staff.Every moment that passes without them fully counted means another conspiracy theory sprouting online."Those days, those were hell for me," said Richer, a Republican who served as the clerk and recorder for Arizona's Maricopa County.
"You'd have a limited number of workers, and you'd have a limited amount of space, and you'd be doing everything that you possibly could.… And yet you have everyone blowing up your phone, everyone saying that you're incompetent or corrupt or worse."This midterm year, election officials in competitive congressional districts will face that same pressure.But they will also face a hard reality: that those races might not be called until days after Election Day.Here's an FAQ on why that is, and what it could mean this year.It comes down to the margin of victory.Which sounds strange, since who wins an election and by how much shouldn't impact how long it takes election officials to count ballots.But the reality is what most Americans think of as "election results" — the winners announced on election nights across TV networks and social media — are not the result of all ballots being counted, but rather, races being called by news organizations that determine the winners based on a state or district's demographics and initial returns.
(NPR relies on The Associated Press for its race calls.)Those determinations come a lot faster when races aren't close."Margins matter," said Richer, who noted that in recent elections, there has been a lot less scrutiny on Utah than there has been on his home state of Arizona, or certain contests in California, despite the states counting votes at similar speeds."In Utah you can call all the races very quickly because the Republicans there have high margins," Richer said....