Students across the state headed back to school this week — but not as many as last year. In fact, according to a report published by the Empire Center on Sept. 4, statewide enrollment is at the lowest level in nearly 30 years.

“We don’t have (enrollment) data yet for ’18-19, but we have tracked that since the ’70s,” said Thomas R. Burns, superintendent of St. Lawrence-Lewis BOCES. “If you look at that entire period, the enrollment has declined significantly.”

Mr. Burns said that enrollment dropped most from the 1970s to about 2000, matching the decline of manufacturing in St. Lawrence County, and has been declining slowly but steadily since the turn of the century.

According to the Empire Center, a conservative think tank, the state has lost about 250,000 students since 2000 — although the decline has not been as sharp in Jefferson, Lewis and St. Lawrence counties as other upstate rural areas in that time.

“We’ve had remarkable stability,” said Stephen J. Todd, superintendent of Jefferson-Lewis BOCES. “I attribute our stability to Fort Drum.”

Student populations may shift with the housing market between districts, but the overall enrollment, he said, has remained more or less the same.

As for St. Lawrence County, it may have already lost many of the students it was going to lose.

“It could be that St. Lawrence County might be pre-shrunk,” said Edmund J. McMahon, the founder and research director of Empire Center and author of the report.

Mr. McMahon says there are several factors contributing to this. In upstate, rural areas, the population overall has decreased and birthrates across not only the state, but the nation, are falling.

“It shadows the overall demographic and economic decline statewide,” he said.

In wealthy areas downstate, he thinks it’s a matter of the cost of living that has driven people out.

There are a few areas — about 100 of the 700 school districts — that have seen an increase in enrollment over the past year. These include poorer upstate cities, like Albany and Syracuse, poorer inner suburbs around New York City and a few wealthy enclaves.

The cities have mostly kept enrollment up through immigrants, but rural areas generally do not have this population influx.

“It’s one thing to observe New York loses too many young people, it’s worse if you don’t have any young people to begin with,” Mr. McMahon said.

Even while enrollment continues to drop, spending on education remains high.

Part of this is inevitable — school districts have high fixed costs that they need to continue meeting. Spending per pupil may be thousands of dollars when the budget is divided, but much of that money goes toward things that need to be paid for regardless of enrollment.

“One added kid in Watertown has no effect on the budget at all,” Mr. McMahon said.

Mr. Todd said that costs may even continue increasing as the enrollment declines, because of obligations like overhead and health care.

“If New York State population went down marginally, you wouldn’t see a decline in the state budget right away,” he said.

Carl D. Korn of the New York State United Teachers said it’s a false equivalency to compare spending on education and number of pupils.

“I don’t think you can conflate them,” he said. “While funding for schools has improved, it still lags behind what is needed.”

Mr. Korn pointed out that about half of students in New York are on free or reduced-price lunch, and while enrollment may be dropping, there are still not enough teachers. Funding education, he said, is an investment in the future of the state, and should be increased.

“Our goal remains the same, and that is that any child, regardless of zip code, has access to a top quality public education,” Mr. Korn said.

Mr. Burns also said increasing numbers of students in the schools have been exposed to traumas of one form or another and may need more support.

“(There are) many more needs than students might have had in the ’70s,” he said. “The school district, the BOCES, we have an obligation to educate every student that shows up at our door in September.”

Still, Mr. Burns thinks that sooner or later the state will have to deal with the consequences of decreasing enrollment.

“Where it really rears its ugly head is at your high schools,” he said.

Elementary classes are relatively easy to “right size,” Mr. Burns said, but small classes in high school make it difficult or impossible to offer more advanced, specific classes.

“It starts to limit the ability to offer a really rigorous and complete secondary education,” he said.

With just a few students in a physics class, say, or none at all, students interested in speciality subjects have to do distance learning, take courses online, or otherwise find ways to pursue classes that students in more affluent, well enrolled schools can take easily.

“Those transcripts look different, and generally that’s a disadvantage for north country students,” Mr. Burns said.

To counteract this, he thinks schools need to be more creative.

“A lot of the areas we could be more responsive to enrollment changes, but we have dozens and dozens of state mandates,” he said. “The state mandates aren’t helpful, that one size fits all.”

Mr. Burns would like to see more flexibility for local districts to deal with the ongoing decline in students.

“Innovation rarely occurs at the state and federal level,” he said.