The number of elementary school students in classes of 30 or more has tripled in the last three years because of teacher attrition and budget cuts to public schools, according to a report released on Monday by a city councilman.
Using data from the city’s Department of Education, the report found that 31,079 students in first through fifth grade were now in large classes, compared with 9,756 in the 2008-9 school year.
Fourth graders and fifth graders are most likely to be in large classes, according to the report, released by Councilman Brad Lander of Brooklyn.
Of current fourth graders, about 14 percent are in classes of 30 or more students, compared with 5.5 percent during the 2008-9 school year. Of fifth graders, about 17 percent were in large classes, compared with 6.5 percent three years ago. The class-size limit for both grades, set by the city and the teachers’ union, is 32 students.
Class-size numbers are normally reported twice a year as citywide averages, showing small increases spread out over many classrooms and over many years. For example, from 2009 to the current school year, the average fourth-grade class grew from 23.4 students to 25.3 students.
However, that data does not reveal how many students are in large classes and whether their numbers are increasing.
“Both the data and common sense tell you that having a kid in a class of 30-plus means the teachers can’t possibly focus on them,” Mr. Lander said in an interview.
Two years ago, when his son was in fifth grade at a Brooklyn public school, the boy’s class size rose to 30 as the school’s financing dropped, he said.
“I loved the teacher, but there’s no doubt in my mind that my son got a lot less attention,” Mr. Lander said.
The report emphasized that there was class-size growth in the fourth grade, a year when students are under pressure to excel on standardized exams used for middle school admissions, but it also found that there were class-size increases for younger students.
There are 11,630 students in first through third grade in classes of 30 or more students, up from 1,162 students in large classes in 2008-9.
These increases could continue in the next school year, according to the report, which quotes from the mayor’s preliminary budget for next year, noting that a $184.7 million cut to general education could lead to the loss of 1,117 teachers through attrition.
City education officials, who did not dispute the report’s findings, said that by the time the budgeting process was over, they expected school financing levels to remain flat.
“We are at the early stages of budget negotiations, but we do not foresee reductions to school budgets next year and we anticipate that schools will be able to maintain their current staffing levels,” a Department of Education spokeswoman, Barbara Morgan, wrote in an e-mail.
Schools in the 39th Council District, which Mr. Lander represents and which includes Carroll Gardens and Park Slope, are in much better shape when it comes to crowded classrooms than are schools in other parts of the city.
In Staten Island, 20 percent of all elementary school students were in classes of at least 30 students. In District 21, which includes Coney Island and Brighton Beach, 19 percent were in large classes. And in District 24 in Queens, which includes Corona, Maspeth, Middle Village and other neighborhoods, 18 percent were in such classes.
Despite a 2007 commitment the city made to reduce class size across all grades, in exchange for more state funding, class sizes have increased in recent years, erasing early gains made during the Bloomberg administration.
Over the last three years, the city has lost 5,300 teachers to attrition and five consecutive rounds of cuts to schools’ budgets, a result of the national recession and decreases in state funding — though the overall budget for city schools has grown.
Responding to a question on Monday regarding Mr. Lander’s report, Deputy Chancellor Kathleen Grimm disagreed with the idea that teacher attrition led to rising class sizes.
“I ascribe the increase in class size to those areas where actually we are continuing to see overcrowding,” she said. “And I think that has more to do with it than anything.”
Citing the costs of reducing class size, as well as studies showing that great teachers can raise students’ performance more than lowering class size, city officials have focused instead on attracting better teachers to the public schools. They have repeatedly said that while class sizes are increasing, the mayor has blocked deeper cuts that would have made for even larger classes.