LOS ANGELES — When it comes to assessing threats, schools in New York City and Los Angeles likely have more experience than most other districts in the country.
But their reactions were dramatically different Tuesday to a similar threat of a large-scale jihadi attack with guns and bombs: LA canceled its classes, while New York dismissed the warning as a hoax.
The divergent responses from the nation's two biggest K-12 public school systems reflected what many in school security know: Deciding whether or not a threat is credible is hardly a mathematical process and the stakes in staying open or closing are high.
It is a move district officials around the country have weighed heavily following school shootings and threats. Districts regularly encounter the challenge of deciphering threats, complicated today by more sophisticated technology that can make them harder to trace.
Even when a threat is determined to be a hoax, the consequences can be a severe, with the safety of thousands of children, millions of dollars in school funding, and the message sent by each decision on the line.
It's extremely rare for a major U.S. city to close all its schools because of a threat, and it reflected the lingering unease in Southern California following the attack that killed 14 people at a holiday luncheon two weeks ago in San Bernardino.
"If this was not ISIS, not a terror organization, they're nonetheless watching," Rep. Adam Schiff, D-Calif., said Wednesday on MSNBC's "Meet the Press Daily." ''And if they come to the conclusion that they can literally mail it in, call it in and disrupt large cities, they're going to take advantage of that."
But one parent bringing her daughter to school as the district reopened Wednesday said no one she knew was second-guessing the decision to close.
"I'm glad they shut it down," said Rebecca Alvarado, who was taking her 5-year-old daughter, Sofia, to an elementary school near downtown. "We're used to it, sad to say, the way the world is."
A 2014 analysis by National School Safety and Security Services, a Cleveland-based consulting firm, found a 158 percent increase in the number of threats schools received over the previous year. About 37 percent of the threats were sent electronically, and nearly a third resulted in schools being evacuated. Nearly 10 percent of the threats closed school for at least one day.
The Los Angeles threat came in an email to a school board member. Authorities in New York reported receiving the same "generic" email and decided there was no danger to schoolchildren. Mayor Bill de Blasio said the threat contained "nothing credible," and New York Police Commissioner William Bratton called LA's closure a "significant overreaction."
But the emails contained importance differences, according to U.S. Rep. Brad Sherman of California, a former chairman of the House Subcommittee on Terrorism.
The Los Angeles message claimed the anonymous author had 32 accomplices, while the New York email cited 138 accomplices, Sherman said Wednesday. Both claimed to be students of the districts they were threatening, but the New York writer's terminology would not be used by someone familiar with that system, while the LA writer's would be, Sherman said.
Officials in California have defended the closure, and so did some parents. Lupe Vasquez had no patience for those on the East Coast who scoffed at the move.
"The New Yorkers were wrong to criticize us," Vasquez said Wednesday after dropping off her 8-year-old daughter at school.
With the San Bernardino attack so fresh, school officials "did what they were supposed to do," Vasquez said.
Victor Asal, chairman of public administration at the State University of New York at Albany, said the decision both districts made was reflective of their respective experiences. New York has invested heavily in homeland security and terrorism response, which might make it easier to process the size of a threat, he said.
"Los Angeles doesn't have that same kind of experience," he said. "So you take the investment New York has, and you take the nervousness that Los Angeles is feeling because it's an hour away from San Bernardino, and that creates a situation where I would expect the two cities to react differently."
Vasya Petrov, 16, said he wasn't nervous to return to class at Downtown Magnets High School. The sophomore spent his surprise day off picking out a Christmas tree with family. But he said after the attacks in Paris and San Bernardino, thoughts of terrorism were never far from his mind.