Principals union president Ernest Logan with Diane Ravitch after Ravitch's speech to union members on Tuesday

City principals should overcome their fear and join with more than a thousand of their colleagues from across the state who oppose New York’s teacher evaluation rules, Diane Ravitch urged during a speech to the principals union Tuesday.

A group of Long Island principals launched a petition in November arguing that the state’s evaluation regulations — which require a portion of teachers’ ratings to be based on their students’ test scores — are unsupported by research, prone to errors, and too expensive at a time of budget cuts.

The petition has attracted nearly 1,300 principals from across the state, but relatively few — just over 100 — work in New York City, in a trend that has persisted since the petition’s earliest days. Sean Feeney, a Nassau County principal who drafted the petition, said in November that city principals seemed to be more afraid of jeopardizing their jobs by speaking out.

Ravitch, a frequent and outspoken critic of the Bloomberg administration’s education policies, took aim at those concerns during the kickoff event in the union’s 50th anniversary celebration. She concluded her speech by exhorting city principals to sign on to the evaluations petition.

“There is strength in numbers,” she said to the roughly 150 current and retired principals in the audience. ”The DOE can’t fire you all.”

Ravitch’s speech, a scathing deconstruction of the city’s achievement claims, drew laughs and applause from the audience. Principals laughed when Ravitch suggested that “value-added” assessments of gym teachers might rely on measurements of how many push-ups students could do. And when she said that judging teachers, students, and schools by a single test each year is “simply ridiculous,” they clapped.

Hearing Ravitch describe the city’s school policies induced “cognitive dissonance” with the picture the city paints, Jeffrey Slivko, principal of M.S. 172 in Queens, told me. Slivko signed the evaluations petition last month.

The union, the Council for School Supervisors and Administrators, recruited Ravitch to speak because morale among pricnipals is low, President Ernest Logan said.

“It’s so important that we have somebody to lift us up,” he said, adding that principals together could “take back public education in this city, this state, and ultimately in this country because we are on the side of right.”

Two members of the Board of Regents, Chancellor Merryl Tisch and Kathleen Cashin, sat in the front row during the speech, held at St. Francis College in Downtown Brooklyn. Cashin in particular has been an outspoken opponent of using test scores to determine a large portion of teacher and principal ratings.