Teacher ratings vary widely among Boston public schools, with many ranking all their teachers either exemplary or proficient while others gave lower marks, according to data released Wednesday in response to a Globe challenge to obtain the public records.
The disparity in ratings raises questions about whether schools that gave all higher marks truly have the most talented teachers or whether a low bar was set for performance. At the other end of the scale, a disproportionate share of black, Latino, and older teachers received low marks, prompting some to worry about a potential bias among evaluators at some schools.
Across the district, 13.5 percent of teachers were deemed exemplary, 79.5 percent proficient, 5.8 percent needing improvement, and 1.2 percent unsatisfactory.
The ratings were given last school year under a new system that attempts to inject more rigor into reviewing the performance of teachers and administrators. The goal is to offer more support for educators who need it, while expediting the termination of those who are failing.
School district leaders said they were encouraged by the initial results but plan to “dig deeper” to understand the disparity in ratings among schools and among teachers of different ethnic and racial backgrounds. Under the system, principals and other administrators evaluate teachers, and central office administrators rate the principals.
“We must not turn back simply because there are patterns that we would not like to see,” interim Superintendent John McDonough told the School Committee on Wednesday night, when he formally unveiled the data.
The School Department has been keeping the full results secret for months.
In May, it released preliminary aggregate data on teachers districtwide but not school by school. It also did not disclose any ratings for principals and central office administrators.
Consequently, the Globe filed public records requests over the summer for aggregate ratings of teachers by school and for administrators districtwide. The School Department refused to release the data, contending that making it public could jeopardize the privacy of its employees, though the Globe did not ask for ratings on individual educators.
Last week, the secretary of state’s office ordered the department to release all the ratings.
As it turns out, ratings for administrators were even more glowing than those for teachers.
Though dozens of schools have among the lowest MCAS scores in the state and many high schools have alarmingly dropout rates, only one principal was deemed in need of improvement and only two principals were rated unsatisfactory.
Similarly, central office administrators were more likely than anyone to receive the highest marks: 36.7 percent were found exemplary, 59.8 percent proficient. Meanwhile, 2.3 percent were in need of improvement and 1.2 percent were deemed unsatisfactory.
The School Department withheld data for 26 schools, where they believe releasing the ratings would compromise the privacy of employees. So there is no data for schools with six or fewer teachers or where all teachers received the same rating.
The School Department also failed to disclose teacher ratings for its in-district charter schools. Brian Ballou, a School Department spokesman, said officials were not prepared to release that data but promised to do so on Thursday.
Richard Stutman, president of the Boston Teachers Union, opposed releasing the data and cautioned parents against using the ratings to make quick judgements on teaching quality at their children’s schools.
He zeroed in on the disparities in rankings among teachers of different races, ages, and genders — a concern he raised last spring after analyzing the data.
“The evidence strongly suggests bias on the part of evaluators and inherent subjectivity in evaluation,” Stutman said.
The evaluations last school year led to the departure from 25 schools of 31 teachers who received a rating of needs improvement or unsatisfactory, school officials said.
But the frequency by which schools rated teachers exemplary showed the widest variations.
Fenway High School deemed 77.3 percent of its teachers exemplary — by far the highest rate. Dottie Engler, co-chairwoman of the school’s board of trustees, said Fenway’s status as a pilot school gives it considerable leeway to hire and dismiss teachers, enabling it to build a high-quality staff.
“They are sensational,” Engler said. “We would put them up against anyone at the exam schools.”
The school’s MCAS scores are higher than state averages and few students drop out.
Other schools also rated more than 40 percent of their teachers exemplary, such as BTU Pilot School, Henderson Elementary School, J.F. Kennedy Elementary, Mather Elementary, Murphy K-8, and Orchard Gardens K-8.
Exemplary ratings, however, were absent at well more than a dozen schools, including Another Course to College, Curley K-8, Clap Innovation, Gardner Pilot, and Haley Pilot.
Boston created its evaluation system to comply with 2-year-old revised state regulations, which established common standards for evaluations and ratings for districts across the state.
Previously, Boston teachers routinely received one of two ratings — meets standards or does not meet standards — if they were evaluated at all.
Under the new system, almost all schools evaluated between 80 percent to 100 percent of their teachers.
But one school, the King K-8 in Dorchester, dropped the ball. The principal evaluated just 5.6 percent of her teachers last year. She has since left the job.
Travis Andersen of the Globe staff contributed to this report. James Vaznis can be reached at email@example.com. Follow him on Twitter @globevaznis.