ST. PAUL — More Minnesota students are taking advantage of the scheduling flexibility and growing online class choices, but a state report released Monday found students taking the classes full-time often fell short of their peers in traditional schools.

The Office of the Legislature Auditor reported that an estimated 20,000 students in kindergarten through high school took at least one online course last year — about 8,000 while attending traditional schools and 12,000 in state-approved online schools. Altogether, that’s less than 3 percent of the state’s K-12 students, the report said, but the number has been growing.

In the 2006-07 school year, about 4,600 students took at least one online course from an online school. By the 2009-10 school year, the number of students taking classes part-time doubled to about 3,800 and the number of students taking online classes full time had tripled to about 8,300.

The report defined students who only took classes online as full-time students while those students that take classes at both traditional bricks-and-mortar schools and online as part-time online students. Students overwhelmingly said they choose online classes for the scheduling flexibility they offered, the report said.

The Legislature requested the report, which included a review of test data, a survey of students and interviews. It found that part-time students tended to do better than students as a whole on standardized tests and much better than students taking online classes full time. That may be attributed to the different backgrounds of the two groups of students, the report said.

Fifteen percent of part-time students were identified as gifted and talented and 8 percent were taking classes to get college credit while in high school. They were also less than half as likely to receive special education services as full-time students. Full-time students also started with lower state tests scores than full-time students, the report said.

“We think there are a number of students — by no means all — who are availing themselves of online learning who haven’t been successful in traditional education,” said Legislative Auditor James Nobles.

During the 2008-09 and 2009-10 school year, full-time online students, on average, made about half as much progress on the state’s standardized math test as traditional students, the report found. The difference was more pronounced in high school. On the 2010 math test, 16 percent of full-time 11th-grade online students passed the state math test while 41 percent of all 11th graders did so.

The report also found that drop-out rates for full-time 12th-grade online students have increased from 18 percent in 2006-07 to 25 percent in 2009-10, while noting that only 3 percent of 12th-grade students statewide dropped out during the 2009-10 school year.

Jon Voss, principal of Northern Star Online, said the poor academic showing is more indicative of the issues the students bring to the programs than anything intrinsic to online education. “It’s the last opportunity students have taken to try and find a way to graduate,” he said.

Voss, who leads a consortium of Minnesota school districts and social service agencies that provide online classes, said there’s really no way to tell in advance if a child will become the sort of well-motivated student who thrives in online classes.

“The difficulty is that you never know who is going to turn into that person in that environment,” Voss said.

Matthew Wicks, vice president of the International Association for K-12 Online Learning, a Washington-based nonprofit, said Minnesota’s experiences with online learning were typical in that 3 to 4 percent of students nationally took at least one online course last year.

He said it was also common for students in full-time online schools to lag behind their peers. Those students often turned to online learning because traditional schools didn’t work for them, Wicks said.

However, he said Minnesota was unusually well situated to handle the expected continued growth in online learning. He pointed to policies the Minnesota Department of Education already had in place to approve new online schools and funding formulas that were already set.

“Minnesota, I would say, is reasonably progressive,” Wicks said.

The auditor, however, was more critical. The report said the state Education Department has struggled with a backlog of applications for new online schools, in part because the budget squeeze has left it with unfilled positions. The report recommends the Legislature set deadlines for reviewing applications.

Deputy Education Commissioner Jessie Montano conceded to lawmakers at a hearing on the report Monday that the unfilled positions within the department have caused a backlog, but said it has been resolved.

Rep. Sondra Erickson, chairwoman of the state House Education Reform Committee, said the state’s policies for online classes would be at the top of her committee’s agenda when it reconvenes in January.

“Online learning is the way of the future,” said the Republican from Princeton. “We have to have quality and it has to have a direction for our students that make sure the courses are rigorous.”