Just Right Reader 1st Grade Classroom Libraries Cohort Efficacy Study

Abstract

This mixed-methods, cross-cohort efficacy study evaluated "Just Right Reader's Classroom Libraries" first-grade students across six schools in a diverse Texas district. The Classroom Libraries consisted of decodable literacy resources appropriately matched to instructional needs and were available in English to all students and in Spanish to the dual language students. Treatment students who used the Classroom Libraries during the 2024-2025 academic year (n = 509) significantly outperformed comparison peers from the previous school year, 2023-2024 (n = 516). Specifically, treatment students had higher end-of-year mClass DIBELS composite scores than comparison students when accounting for mid-year performance ([beta] = 3.12, p = 0.002). This represented approximately 5% additional literacy growth over the course of one semester. Students using the Classroom Libraries also demonstrated greater subdomain gains in letter sounds, word reading, decoding, and reading fluency (p's < 0.05), as well as significantly higher NWEA MAP Reading RIT score growth (+4 points, p < 0.001) among classrooms reporting consistent engagement with the Classroom Libraries. Qualitative feedback from educators indicated increased student engagement, confidence, and reading fluency among students using the libraries. Overall, our research suggests that "Just Right Reader's Classroom Libraries" provide an effective approach to strengthening foundational reading skills and promoting equitable literacy development in first grade.