“They just added another student to Nolan’s class,” my friend Brad told me yesterday. “Now they’re up to 31 kids. How did this happen?”

When confronted with the issue of high numbers of pupils in Juneau classrooms, School District officials typically point to the Alaska legislature: “We feel your pain,” they say, “But they dropped our funding!” And while this is certainly true, Nolan’s overcrowded 5th-grade classroom at Auke Bay Elementary School is also an outcome of how our School Board chooses to prioritize District expenses, and about how they decide to carry out — or to not carry out — their business.

The number of pupils in your child’s classroom depends upon how many teachers are employed at their school. And the basis for establishing that number begins in February, with an estimate of how many kids will be enrolled in the upcoming year. The School Board adopts a pupil-to-teacher ratio (PTR) then simply divides the estimated number of kids by the PTR to determine how many teachers they will hire. Currently, the board has chosen PTRs of 22.0 for grades k-2, and 26.5 for grades 3-5.

In Nolan’s case, the district estimated his school would have of 155 pupils in grades 3, 4, and 5. Then they divided 155 by the PTR of 26.5, with a result of 5.8. The policy calls for “rounding up or down”, so they allocated 6 teachers to instruct grades 3 through 5 in his school.

But with a PTR of 26.5, how did Nolan end up with 31 kids in his class? It’s a result of averaging the PTRs across three grades. His 5th-grade class represents a “bulge” in enrollment; grades 3 and 4 have numbers that are actually below the PTR of 26.5, but the 5th-graders are stuffed like herring in a seine net, and poor Nolan’s education is suffering from it.

Along with bulges, there are other situations that can cause high numbers of pupils in your child’s classroom. Each of them points back to school district actions.

Nolan’s overcrowded classroom is not only a product of the district’s high PTR and an enrollment bulge, it’s also the consequence of the district having no rules for an upper limit on the number of pupils that can be placed in an elementary school classroom. Does anyone care to place a bet on how big Nolan’s classroom will get before the problem is addressed?

And in other cases, over-stuffed classes come from enrollments that greatly exceed the February estimates, and not enough teachers are allocated when the school year begins. When the school board shrugs their shoulders and decides to ignore any adjustments, you end up with what is happening to the kids at Harborview this year, with teachers who can’t effectively teach, and 26 five-year-old kids bumping shoulders in kindergarten classrooms that were designed for about 30 percent fewer students.

And in still more cases, huge numbers are simply a reflection of the high PTRs adopted by the board in the first place. To meet their expenses, the board has raised PTRs in elementary schools for the last 3 consecutive years, and we now commonly see unacceptably high numbers in classrooms throughout the district, even if the PTR formulas are strictly adhered to.

And finally, and maybe most troubling, overcrowding can relate to the philosophies of some school officials, who simply don’t believe that crammed classrooms should be placed very high in the budget priorities. To support their position, they make vague references to “the research” and ideas that Bill Gates has floated (“Let’s pay teachers more, then raise class sizes!”), all the while ignoring a large body of science, and common sense, that points to how crucial classroom sizes are to early learning.

In any event, this is your chance to make a difference. Tell your school board they should abandon their current high PTRs and insist that they adopt lower levels in next year’s budget. Point out they should never “round down” when allocating teachers to schools, and make them establish an upper limit on how many students can be in a classroom. Then advocate for a policy of solving problems that come about when actual enrollments stray far from projections, with provisions that the district treat all schools equally. And tell them to apply common sense to their notions about classrooms: that smaller class sizes do make a difference, and that as our elected officials, we put it in their hands to make it happen.

• Iverson of Juneau is a parent of two children who attend elementary school in the Juneau School District.