Minnesota has a decades-long history of going the extra mile to serve students with special needs, but now that going above and beyond is taxing local school budgets, it makes sense to revisit the rules. Policymakers should consider whether there are better, less costly ways to help kids with milder disabilities.

The average annual cost for a general-education student is $8,486, compared with $22,144 for special-education kids. Those with the most severe disabilities can cost $100,000 or more. In Minnesota, the cost of special education rose to $1.8 billion this year (up 70 percent in the last decade) and forced many districts to divert revenues from general education.

As a Star Tribune news story documented this week, some of that increased expense comes from providing services for kids diagnosed with milder forms of autism and emotional behavioral disorders. That practice helped increase special-education enrollments in Minnesota, even as national numbers have gone down. In many other states — and under federal rules — those students would not even be eligible for special education.

Earlier this year, a legislative auditor's report suggested smart ways to address numerous "disincentives'' that stand in the way of controlling costs. It found, for example, that about 75 percent of state special-education rules exceed what is required by federal regulations. And, the report noted, some of Minnesota's statutes are inconsistent with the rules of its Education Department.

Researchers have said that some school leaders "overprovide'' special services, under the logic that giving in to parental demands can be less expensive than lawsuits. To address that concern, the state can do more to clarify differences in state and federal law and to help educators understand exactly what they are obligated to provide.

Another way to rein in costs would be to prevent the need for special education for some students to begin with. Some schools locally and nationally have tried a strategy called Response to Intervention that identifies struggling students early and gets them extra help, which can be as simple as math lessons in small groups. Using RTI, a Wisconsin school significantly dropped its percentage of special-needs pupils.

Following the auditor's report, the Education Department convened a special-education task force to examine ways to reduce paperwork and study caseloads. The group has met twice, including once this week. Its members should also consider other auditor recommendations — including conducting an independent analysis of the changes to state special-education regulations.

The state and federal governments mandate special-ed services but fund only about two-thirds of the cost. The other third is covered by school districts. That has led to difficult debates about how much districts can afford to spend on special education.

Ideally, the other units of government should fully fund the mandates they impose. During the 2013 session, Minnesota lawmakers put an additional $40 million into special education, which will help. But the federal government hasn't picked up its fair share and doesn't appear motivated to do so any time soon.

Minnesota was the pioneering state in offering special-education programs, requiring those services beginning in 1957, nearly 20 years before any federal laws were passed. While it's admirable to try to do as much as possible for all students, tighter budgets and growing needs call for difficult choices. This has been true across the board, in areas ranging from health care to public safety to social services. As one of the fastest-rising costs, special education merits that kind of review as well.