This randomized controlled study was conducted in 99 matched high schools from 46 districts in California and Arizona that serve high proportions of African American, Latino, and English Language Learner (ELL) students. 159 teachers participated in ten days of Reading Apprenticeship teacher professional development in science and history.

Teacher surveys and interviews indicate that teachers of both subjects were equipped to provide more engaging subject area and literacy instruction than control teachers over the year following professional development. In addition, scoring of teacher assignments ranking subject area and literacy instruction showed that treatment teachers provided more effective assignments than control teachers.

The standardized test scores of Biology students suggested they were well over a year ahead of control students. The standardized test scores of History students in both history and reading comprehension and English language arts suggested they were also well over a year ahead of the control students on all three of these measures.