Hundreds of Albuquerque students walked out of school in March to protest new tests aligned to the Common Core State Standards. (Roberto E. Rosales/Albuquerque Journal via AP)

A dozen civil rights groups issued a statement Tuesday criticizing the growing movement of parents who refuse to allow their children to take standardized tests, saying the anti-test push “would sabotage important data and rob us of the right to know how our students are faring.”

By removing an increasing number of students from the testing pool, the so-called opt-out movement skews test score data, the groups argued, making it impossible to gauge whether persistent achievement gaps are narrowing.

“We cannot fix what we cannot measure. And abolishing the tests or sabotaging the validity of their results only makes it harder to identify and fix the deep-seated problems in our schools,” the statement said.

The groups that signed the statement included the Leadership Conference on Civil and Human Rights, the NAACP, the National Council of La Raza, the National Disability Rights Network and the National Urban League.

Students who refuse tests are still a tiny minority of all test-takers nationwide, but their numbers are growing. The resistance has grown this spring as most states have rolled out new tests aligned to the Common Core academic standards.

New Mexico junior Laura Cruz, 18, was among those who walked out to protest new standardized tests. (Robin Zielinski/Las Cruces Sun-News via AP)

Many parents who are refusing to allow their children to test consider it an act of civil disobedience meant to protest what they say is a destructive emphasis on testing that has warped public schools.

In their joint statement Tuesday, the civil rights groups said they recognize that standardized tests have been “misused over time to deny opportunity and undermine the educational purpose of schools, actions we have never supported and will never condone.”

But they said that they rely on the data from those tests to advocate for poor and minority children, who face worse outcomes on every measure, academically and otherwise, than their white and affluent peers.

“For the civil rights community, data provide the power to advocate for greater equality under the law,” they wrote. “Until federal law insisted that our children be included in these assessments, schools would try to sweep disparities under the rug by sending our children home or to another room while other students took the test. Hiding the achievement gaps meant that schools would not have to allocate time, effort, and resources to close them. Our communities had to fight for this simple right to be counted, and we are standing by it.”

Earlier this year, about twice as many civil rights groups signed onto a joint statement asking Congress to maintain annual standardized tests in the next version of No Child Left Behind, the main federal education law.

Federal law requires schools and school districts to ensure that at least 95 percent of students take annual standardized tests. The rule is meant to keep administrators from quietly discouraging low performers to stay home on exam day, something that could skew performance upward and hide racial or socioeconomic inequities.

In some pockets of the country — including in school districts in New York, New Jersey, New Mexico and Ohio — the proportion refusing tests far exceeds 5 percent.

Some superintendents in New York have reported that more than 60 percent of eligible test-takers have refused tests this year, according to the Associated Press. At one Seattle high school, the entire junior class refused to show up for a standardized test last month.

Federal money can be withheld from school districts with low participation rates, but that has not happened in the past and is not yet clear how or whether officials might actually sanction schools and school districts with low participation rates this year.

Read more:

Is it is a civil right to take a test?

Civil rights groups back testing in No Child Left Behind rewrite