A lawsuit filed by a pair of Massachusetts families is adding to the backlash against an approach to reading instruction that some schools still use despite evidence that it’s not the most effective.

States around the country have been overhauling reading curricula in favor of research-based strategies known as the “science of reading,” including an emphasis on sounding out words.

The lawsuit takes aim at approaches that do not emphasize phonics. Among them is the long-established “three-cueing” strategy, which encourages students to use pictures and context to predict words, asking questions like: “What is going to happen next?,” “What is the first letter of the word?,” or “What clues do the pictures offer?”

Families of Massachusetts students who have struggled to read filed the lawsuit against authors and publishers endorsing that approach, including Lucy Calkins, a faculty member at Columbia University’s Teachers College. It seeks damages for families allegedly harmed by the material.

Thousands of schools once used three-cueing as part of the “balanced literacy” approach championed by Calkins and others that focused, for example, on having children independently read books they like, while spending less time on phonics, or the relationship between letters and sounds. Over the last several years, more than 40 states have enacted bills emphasizing instead materials grounded in evidence and scientific research, according to the nonprofit Albert Shanker Institute.

It’s unknown how many school districts still use the contested programs because the numbers aren’t tracked—but there are many, according to Timothy Shanahan, a professor emeritus in education at the University of Illinois at Chicago. Many teachers have been trained to teach three-cueing so it may be used even in classrooms where it’s not part of the curriculum, he said.

He said research does show benefits from teaching phonics, but there is less information about the three-cueing method.

The suit asks the court to order the authors, their companies and publishers to provide an early literacy curriculum that incorporates the science of reading free of charge.

This article was provided by The Associated Press.