The newest math scores for Minneapolis South High School's 11th-graders plunged more than 25 percentage points compared with 2013. At Southwest High School, scores dropped 22 points over the same period.

The dramatic fall off at two of Minneapolis' best schools is not because of a crisis of academic achievement, but rather historic numbers of top students who are exercising a little-known right to opt out of standardized tests.

Plunging test scores have become the latest outcropping of an intensifying feud over teacher accountability and mounting criticism nationally of make-or-break standardized tests.

The opt-out effort is being led by a growing group of parents and teachers skeptical of testing's results and who believe that the push for more testing is driven largely by the nearly $1 billion testing industry.

"The system that we have is pitting teachers against students," said Valerie Olsen-Rittler, a National Board Certified teacher in Minneapolis and a parent. "If you have teachers that are going to be judged based on students' scores, that destroys the relationship between the teacher and the child."

School district officials say they expect more declines in average test scores as more students decide against taking the exams. The surge in students opting out over the past two years is making it harder for the district to measure mastery of math and other core subjects.

"There are unintended consequences of opting-out," interim Minneapolis Superintendent Michael Goar said. "I am respectful of parents making the decision to say, no, I am not going to participate. But on the same token I think it's critical for all of us to understand the impact of opt-out."

State and district officials say students have a legal right to opt out of exams, but say they are concerned schools will be unable to accurately track student progress or evaluate how well schools are doing in closing achievement gaps between white and minority students.

Parents and teachers who support the movement say this is an ideal moment to draw attention to the negative effects of testing on students, teachers and the entire educational system.

"Tests being used as final judgments of who students, teachers and schools are is taking real education transformation in the wrong direction," said Lynn Nordgren, president of the Minneapolis teachers union. "It is time to expose the insanity of it all and change direction."

Rapid growth

Statewide data for how many students opted out of state exams this year is not yet available, according to the state Department of Education. In 2014, 301 11th-graders opted out of state math tests statewide, up from just 18 in 2013. The majority of opt-outs, 254 of them, came from Minneapolis' South and Southwest high schools in 2014.

Eric Moore, Minneapolis' director of research, evaluation and assessment, said opt-outs are predominantly white, middle-class students who skew toward being gifted learners.

Moore estimates opt-outs increased slightly this year, from 2 percent of all students to 3 percent. Although the overall number of those choosing not to take the assessments are small, Moore said the district is now losing a key data point that it uses to determine a student's growth and progress at certain schools. The test scores are also used as one component in evaluating teachers.

"As a parent that is their right. It's a critical one that families are making," Goar said of those who opt out of testing. "But I do want to make sure that it is a parental decision. I don't want other adults, for their political perspective or their belief system, pushing that onto families."

'Unintended consequences'

A new problem for Minneapolis school leaders is that the opt-outs have caused misleading student achievement data. Minneapolis schools have already been a target of charter schools and other groups that for years have seized on the district's lagging test results.

Better Ed, a nonprofit group that has relentlessly advocated for the dismantling of the Minneapolis School District, highlighted the drop in Southwest's scores almost immediately.

"Trouble at Minneapolis' best high school," the group wrote, highlighting the drop in math scores. "It's troubling to see that Southwest's students are regressing in a subject so critical for their futures."

Better Ed Vice President Daniel J. Lattier said he was later told why the scores had dipped and agreed that the opt-out movement is concerning.

"I don't think anyone claims standardized tests are perfect," Lattier said. "I understand some of the reasons for the movement, but I haven't heard what other form of accountability really looks like."

Alejandra Matos • 612-673-4028