A bill to make class sizes a mandatory topic of bargaining between Oregon school districts and their local teacher unions appears poised to clear a key hurdle in Salem this week.

Should the concept pass win approval from the House and Senate, it could radically reshape learning conditions for high-needs students, especially in larger districts with schools of varying poverty levels.

Chief among its effects could be to reduce class sizes in high-performing schools that serve the children of comparatively well-off families at the expense of students in schools that serve more children from families with low income or education levels.

That’s because many districts with schools of varying needs allocate extra teachers to schools with a lot of special education, low-income or English language learning students, who need extra individual attention to soar. Setting one-size-fits-all class size caps in the absence of a big infusion of money typically translates into subtracting teachers and support staff at those schools to create more uniform classes at all schools.

Absent the mandate to let unions help set class sizes, some districts have found a lower-cost way to get around that challenge by offering bonus pay to teachers facing the heaviest class loads.

The proposed $11.4 billion statewide outlay for K-12 schools over the coming two years would give school districts enough money to maintain current service levels but not to add hundreds of new teachers or even keep as many as they have, given declining enrollments.

That means that should the Legislature pass House Bill 3652, school districts that agreed to class size caps in negotiations might be faced with cutting days off the school year to balance their budgets.

Class sizes around Oregon have dropped since before the pandemic, as public school enrollment has declined.

In the 2023-2024 school year, the median class size was 22.5 and there were 24,360 teachers statewide for about 523,000 students, according to data released this month by the Oregon Department of Education. In the 2018-2019 school year, by contrast, the state’s data shows that the median class size was 25 and there were 24,374 teachers statewide for 556,000 students.

Under current Oregon law, districts are only required to negotiate class sizes for schools that receive federal Title I funding, which is targeted to high-poverty schools.

Teachers have packed hearings to testify to the importance of smaller class sizes regardless of their students’ demographics. Research has shown that reducing class sizes to very small levels can make a big impact in early elementary grades, particularly for high poverty populations. But it also shows that the impact diminishes as children age and that the strategy is much less cost effective than others, like making sure there is a highly effective teacher in every classroom.

Kori Bass, a fourth grade teacher at Lewis Elementary School in Portland, where 23% of students qualify for federal poverty aid, wrote to lawmakers to say that in 20 years of teaching, her largest class sizes have all come in the last seven years, including classes as large as 34 students.

“In classes this size, students do not get the individual attention that they need and deserve,” she wrote. “Unfortunately, everything takes so much longer to teach, resulting in less content coverage throughout the year. Students with behavioral issues in the classroom dominate the space and require the most attention … Teacher burnout when teaching classes over 25 is inevitable.”

She and other teachers noted that if the bill passes, it would not obligate districts to meet a certain class size, just that they would have to reach agreement with teachers unions on the topic during contract negotiations. Four other states have similar laws on the books, according to the National Council for Teacher Quality: Massachusetts, Minnesota, New Jersey and California.