Nearly 4,000 charter school officials are expected to gather in Minneapolis this week to discuss the progress of the national movement -- which began 20 years ago when the nation's first charter school opened in St. Paul. Enrollment at charter schools in Minnesota has surged in the last decade, but the effectiveness is still being debated. MPR reports a new University of Minnesota study found students at Twin Cities area charter schools scored lower on math and reading tests than counterparts at traditional schools.

It was twenty years ago when America's first charter school opened in St. Paul. One of the key state lawmakers in the movement says much of the credit belongs to a group of active citizens. Today there are more than 5,000 charter schools around the country. A national convention will meet in Minneapolis this month.

A new report from the St. Paul-based Center for School Change found enrollment in Minnesota charter schools has grown to just under 40,000 students. Meanwhile, enrollment at traditional public schools fell five percent in the same time period. Minnesota's first charter school opened 20 years ago in St. Paul.