The 53 schools that have been investigated for possible cheating – one in five of all district schools – come from every part of the city and span every grade level. Some had been labeled “Vanguards,” a Philadelphia School District designation for its highest-achieving schools, and one that gave them flexibility in curriculum and budgeting.

In recent years, testing scandals have erupted in Washington; Cincinnati; Baltimore; Detroit; Houston; Los Angeles; and Newark, N.J., among other cities. Since 2009, cheating has been confirmed in 37 states and Washington. The Philadelphia scandal has drawn comparisons to one in Atlanta, where last year a Fulton County grand jury indicted 35 educators, including Beverly Hall, a former school superintendent. The allegations touched at least 44 schools.

Robert McGrogan, head of the union that represents Philadelphia school administrators, said he does not condone cheating under any circumstances. But, he said, during the years of the alleged cheating, the district was a pressure cooker. “Do you know how many of us sat in meetings with our bosses and were told, ‘You have to bring your scores up’?” said McGrogan, a principal at the time. “There was no how-to book given to us.” Supervisors warned principals that if they did not meet state standards, “you’re not going to be a principal next year,” McGrogan said.

Jerry Jordan, president of the Philadelphia Federation of Teachers, said he doesn’t condone cheating …