The fragile edifice of the caucuses, which demoralized Democrats in search of a strong nominee to take on President Trump, crumbled under the weight of technology flops, lapses in planning, failed oversight by party officials, poor training, and a breakdown in communication between paid party leaders and volunteers out in the field, who had devoted themselves for months to the nation’s first nominating contest.

The wider scope of the malfunctions came to light partly because of a new set of reporting requirements, mandated by the Democratic National Committee after allies of Senator Bernie Sanders of Vermont pushed the national party to demand more transparency following his narrow loss to Hillary Clinton in the 2016 Iowa caucuses.

The widespread lack of faith in the Iowa results has shaken many Americans’ confidence in their electoral system. Mr. Trump has reveled in the meltdown. Democrats have proposed abolishing caucuses and ending Iowa’s time at the front of the presidential nominating calendar.

Even as party officials scramble to contain the fallout, the full extent of the problems in Iowa is still not known.

An analysis by The New York Times revealed inconsistencies in the reported data for at least one in six of the state’s precincts. Those errors occurred at every stage of the tabulation process: in recording votes, in calculating and awarding delegates, and in entering the data into the state party’s database. Hundreds of state delegate equivalents, the metric the party uses to determine delegates for the national convention, were at stake in these precincts.

The Iowa Democratic Party released a list of 92 precincts on Sunday that it said were flagged as problematic by three presidential candidates — Mr. Sanders; Pete Buttigieg, the former mayor of South Bend, Ind.; and Senator Elizabeth Warren of Massachusetts. That figure is far fewer than the number with inconsistencies captured in the Times review. The Associated Press said it was unable to declare a caucus winner.

Sean Bagniewski, the Democratic chairman of Polk County, which includes Des Moines, blamed state officials for neglecting the hard work of overseeing the caucuses.