BOSTON — Thousands of students in Massachusetts move between public school districts every year, taking millions of dollars in state education funding with them.

Critics say the system is flawed, and they are pushing to change how the money is allocated.

Under inter-district school choice, parents have the option of enrolling their children in a community other than their hometown. While public school districts can decide whether to accept out-of-district students — about 40 percent don’t participate — they cannot hold back students who want to move elsewhere.

Since the program was rolled out nearly three decades ago, the number of students moving around has grown to more than 17,000, according to the Department of Elementary and Secondary Education.

Tom Scott, executive director of the Massachusetts Association of School Superintendents, said school choice is a mixed bag.

“For receiving districts, it works pretty well,” he said. “But the problem is that low-performing districts that are losing students end up losing money that they can ill afford to lose.”

In some cases, however, districts that lose students through school choice end up making money.

The reason is, under the school choice program, districts still receive state education aid for students who’ve left. While those districts must pay students’ tuition at their new schools, the state caps the fee at $5,000 per student per year.

One proposal, filed by Senate Minority Leader Bruce Tarr, R-Gloucester, calls for increasing the tuition cap to $6,500 per student.

School choice advocates like the Pioneer Institute, a Boston-based think tank, say raising the cap will create a fairer system.

Last year, Pioneer released a report noting the cap hasn’t kept pace with inflation, or overall education spending.

“The increases should be high enough to incentivize more high-performing districts to accept non-residents,” the report’s authors wrote. “But there needs to be a balance between those amounts and the need to maintain fiscal stability in the sending districts.”

Pioneer has also recommended raising an overall cap on the program, now set at 2 percent of statewide public school enrollment.

The Pioneer report noted school choice has become a “budget tool” for some high-performing districts that actively recruit students from economically challenged areas.

“School committees actively seek non-residents not just to fund special programs, but to balance their budgets,” the report’s authors noted.

Losses and gains

Under the current design, districts can gain or lose significant money from their budgets due to school choice.

Gloucester, for example, expects to lose more than $2 million in state funding due to 297 students leaving in the current school year, according to the Department of Elementary and Secondary Education. In the meantime, the district will only will bring in $292,301 from 42 pupils coming from other communities.

Lawrence schools stand to lose $424,955 from 62 students moving to other districts, but hasn’t received students this year from the program.

Same goes for Methuen, which expects to lose 42 students this year with $342,907 in funding that will follow them to other communities.

Some districts, like Peabody and Rockport, are gaining state education funding from the school choice program.

Peabody expects to receive $640,213 from 113 students coming from other communities, while losing $330,377 to 49 students opting out.

Rockport is receiving 250 students this year, which will bring more than $1.7 million in funding, and losing 34 at a cost of $257,914.

A recent state report looking at the impact of school choice on rural districts was also critical of its effects, concluding that it has “created a situation where districts are competing with one another over an ever diminishing population of students.”

Christian M. Wade covers the Massachusetts Statehouse for The Salem News newspapers and websites. Email him at cwade@cnhi.com