HENDERSON, Nev. — One voter was under the mistaken impression that he had come to a primary, not a caucus. Another had planned to vote for former New York mayor Michael R. Bloomberg, only to discover he was not on the ballot. And a third had a multipart procedural question for the volunteer running his precinct caucus at Coronado High School.

“If I understand correctly,” the voter said, “everyone will decide on who they’re for, and then you’ll tell us the data about how votes from the early voting breaks down, and then we’ll add the totals, and anything above 13 for any candidate will be considered viable?”

Well. Kind of.

Caucuses are at once wondrous things — democracy at its most granular and visceral — and at the same time confusingly complicated exercises in political anachronism. Only a handful of states still use them. And after the debacle over counting and reporting votes in Iowa earlier this month raised questions about whether caucuses even make sense any more, Nevada was determined to prove that its process would be smooth and effective.

“It puts a tremendous amount of pressure on us to make sure we are running an open and transparent caucus with plenty of ways to verify that a person showed up and voted,” said Mandie McCurdy, a site leader at Coronado, which performed the impressive and messy high-wire act of holding simultaneous caucuses for 13 separate precincts on Saturday.