LOS ANGELES (AP) — The same organization that backed a landmark case on California’s teacher tenure laws is funding a lawsuit filed Thursday that takes aim at districts not enforcing an act that requires student achievement data to be used on teacher evaluations.

The suit filed by four parents and two teachers in Contra Costa County Superior Court alleges 13 districts around the state have signed collective bargaining agreements that explicitly prohibit compliance with the 1971 Stull Act.

The suit states that the districts fail hundreds of thousands of children by refusing to enforce the law.

The plaintiffs are backed by the non-profit group Students Matter, founded by Silicon Valley entrepreneur David Welch.

Students Matter also funded plaintiffs in the 2014 Vergara v. State of California ruling that found five California Education Code provisions — including policies allowing teachers to receive tenure within two years and be dismissed during layoffs on the basis of seniority — were unconstitutional because they deprived some of the state’s 6.2 million students of a quality education.

Superior Court Judge Rolf M. Treu said the statutes particularly burdened poor and minority students.

The new lawsuit aims to force districts to comply with the Stull Act, which requires districts to evaluate teachers based on four criteria, one of which is student progress as measured by performance on state assessments, when applicable.

The suit targets San Ramon Valley Unified, Chino Valley Unified, Saddleback Valley Unified, Chaffey Joint Union High School District, Ontario-Montclair, Fairfield Suisun Unified, Antioch Unified, Inglewood Unified, Victory Elementary School District, Upland Unified, Pittsburg Unified, Fremont Union High School District and El Monte City School District.

A total of about 250,000 California students attend those districts.

“In the absence of proper evaluation of teachers, school districts cannot reasonably know whether teachers are actually promoting and advancing student learning over time,” the lawsuit states.

Joshua Pechthalt, president of the California Federation of Teachers, said the districts named in the lawsuit have negotiated teacher evaluation systems that make sense for them and would fight the lawsuit.

He also criticized Students Matter and the new lawsuit as representing “the education agenda of billionaires and corporate America and the one percent.”

The legal action comes at a time when there has been a growing backlash against the use of standardized tests in the nation’s schools.

John Rogers, an education professor at the University of California, Los Angeles, said there is still considerable dispute among researchers about the role student data, and in particular, value-added measures, should play in teacher evaluations.

He said too often the debate has focused on using student data to identify which teachers should be fired — rather than incorporating that data into professional development and helping teachers improve.

“The policy problem we have is not who to fire,” he said, “but how do we bring more teachers into the profession? Because increasingly, we are facing shortages again.”