MINNEAPOLIS — Most of Minnesota’s school districts are ready to implement new teacher evaluations this fall, but some of the 333 districts are still developing plans.

“Roughly three-fourths of our school districts have plans ready to go,” Denise Specht, president of the state teachers union Education Minnesota.

The rest have work to do.

“School districts are right now ‘MacGyvering’ what they’ve got to fit the law,” she said.

In 2011, lawmakers revamped Minnesota’s teacher evaluation law. It requires formal evaluations for new teachers each year for three years. They’ll also meet regularly with veteran teachers.

Under the old system, some teachers went a decade or longer without receiving proper feedback.

Experienced teachers will now receive a formal evaluation once every three years. Teachers’ performances will be based on how well their students are doing academically and how well they handle a classroom, based on observations by administrators and other teachers.

The law requires districts to develop evaluation systems with their local teachers unions. They need to be approved by both union members and school boards before Sept. 1.

Tyler Livingston, educator evaluation specialist for the Minnesota Department of Education, said the department, the state teachers union and the Minnesota Association of School Administrators are helping districts.

One option for districts is to use an evaluation model developed by state education officials. This school year, 17 Minnesota districts tried using some or all of the state model.

Among them was the Caledonia district in southeastern Minnesota, which received a $70,000 state Department of Education grant to test the system. Superintendent Ben Barton said the new system was a big improvement.

“It’s taking us away from the days where teachers close their doors and are taught in a silo and did their own thing,” he said.