At a time when overall Minnesota school enrollment is declining, enrollment in charter schools in the state soared by a record number last year, according to a study released Thursday.

The study, conducted by the Center for School Change at the University of Minnesota's Humphrey Institute of Public Affairs, found that the number of students attending charter schools rose by 4,337 during the 2007-08 school year. That marks the biggest enrollment increase since 1991-92, when the charter school option was first made available to Minnesota students and parents.

Total enrollment for charter schools stands at 28,206. That's almost three times the enrollment in the 2001-02 school year. The total public school enrollment last year in Minnesota was 796,757, a number that has been declining for several years.

"We knew that many families were selecting charters, but were surprised to learn that there was a record increase last year," said Joe Nathan, one of the report's authors, and a charter school booster.

The number of Minnesota charter schools has increased from two in 1992-93 to 143 last year, according to the study. Charter schools are public schools that are set up with particular types of students or learning emphases in mind. They are allowed more flexibility in how they operate than typical public schools.

Nathan cited several reasons he thinks have fueled the spike in charter school enrollment.

"First, small size of the schools," he said. "Secondly, safer schools. Third, distinctive programs, whether they're language immersion ... the arts, things like that. Fourth, there's a feeling of great respect from teachers to parents and from teachers to students."

The study also found that more than half of the students in Minnesota's charter schools are racial minorities. More than half also are low-income students.

Norman Draper • 612-673-4547