For the fourth straight year, the state Department of Education has extended a waiver that allows school districts to exceed class size limits.

A local school board must take a public vote on whether its district will exceed class size limits, which vary greatly based on grade level and academic subject matter. Federal rules also determine the size limits of some classes.

The waiver was extended to give school districts financial relief. Many are still reeling financially and aren’t replacing teachers who leave, opening the door to rising class sizes.

“While we don’t like having to ask the board for a waiver of the class-size rule, our districts need this flexibility right now so they can continue to operate school each day,” Georgia Superintendent John Barge said. “If one or two students were to move into some of our schools, it would put their classes over the maximum, causing them to hire another teacher that many districts can’t afford.”

It’s not clear how much class sizes have risen over the past four years; there is no comprehensive, precise tracking of class sizes in Georgia.

It’s also not clear what impact larger class sizes have on teaching and learning.

Some studies show that large class sizes aren’t always an impediment.

A study released in 2012 by the National Bureau of Economic Research, a nonprofit group that studies economic factors, said frequent teacher feedback, data-driven instruction, intense tutoring, increased instructional time and high expectations all matter more than class size.

Teachers, however, say it’s easier to manage and teach in classes with fewer students.

“It’s ideal to have lower class sizes because you can have more one-on-one,” said Pam Heslep, a kindergarten teacher at Craig Elementary in Gwinnett County with 30 years of experience.

Heslep said her district has made sure she’s had extra resources when she has a large class. This year, she has a class of 27 students, and she’s gotten help from a paraprofessional, a sort of co-teacher.

“It’s helpful to have another pair of hands in there,” Heslep said.

State Board of Education members expressed some unhappiness about extending the state class-size waiver. They made it clear that districts don’t have to use the waiver but can still adhere to the limits.

“What this does is it puts it on the system to make the decision,” board member Mary Sue Murray said. “Believe me, we never like doing this. We never like to raise class sizes. But hopefully times will get better.”

Verdaillia Turner, president of the Georgia Federation of Teachers, said districts are under financial pressure because state leaders have not placed a high enough value on traditional public education and instead have put their faith in school-choice options such as charter schools or private schools.

“The public is still being misled as to what the solutions are in education,” Turner said. “The state continues to create very costly pathways in which to steer the people’s dollars. So-called “choice” is one of those pathways.”