New policy adjustments from a regional college accreditation group could unnecessarily limit the opportunity for Minnesota high school students to take college courses. Earlier this year, the Higher Learning Commission, an agency that accredits colleges and universities in 19 states, approved rules that require high school educators to have master's degrees or graduate-level credits in the college-level subjects they teach.

Many high school teachers don't have those credentials. That prevents them from teaching College in the Schools courses, meaning students will be denied opportunities to earn college credit at their high schools.

The commission should rethink its decision, or at the very least allow some exceptions for concurrent-enrollment programs.

Minnesota's program has proved its effectiveness since it began 30 years ago even though many of its high school educators don't have master's degrees. During the last school year, 24,000 Minnesota students enrolled in dual-credit courses, up 30 percent since 2009.

Studies show that dual-credit students do better in school and have higher high school graduation and college attendance rates. A Minnesota Department of Education report, for example, said that 94.7 percent of all students who took one or more concurrent-enrollment courses graduated from high school during the 2012-13 school year. That's nearly 20 percentage points higher than the graduation rate for all Minnesota teens. In addition, dual-enrollment students tend to have higher academic achievement across the spectrum of student groups, including students of all races and incomes.

Another program benefit is that it saves Minnesota families millions in higher-education costs. A study of the 2013-14 College in the Schools program at the University of Minnesota's Twin Cities campus shows that the credits earned by high school students would have cost them about $24.4 million. That's an important benefit for students and families, one that is especially welcome in a state that ranks fourth in the nation in college debt. Students attending Minnesota colleges leave with an average debt of slightly more than $31,000.

Commission representatives said that they have expected all educators teaching college-level courses to meet the standards but that they found that some institutions were allowing some without those credentials to teach. So the commission's board voted to make the credentials an explicit requirement to ensure that courses are sufficiently "rigorous.'

There's no evidence that dual-enrollment students in Minnesota have suffered from lack of rigor. To the contrary, students in the program are better prepared for college work because they've been exposed to it in high school. And their high school educators are trained and monitored by local college professors.

State education officials say that the program has demonstrated its value and that it has been especially helpful in improving access to college for low-income and minority students, particularly in rural areas. The concept is working so well that the Legislature approved more than $4 million this year to add dual-enrollment classes across the state.

Two legislators who support the program wrote to the commission and asked officials to explain the policy change at a hearing. They rightly object to the move and hope to persuade the group to make adjustments before the changes take effect in 2017.

Higher Learning Commission policies include provisions that allow teaching assistants and experienced professionals to teach courses. It could use similar language to allow adequately trained and supervised Minnesota high school instructors to continue to teach college-level courses.