This study used latent growth models to compare growth in oral reading skills over one year for students using 6 different reading curricula: Open Court, Reading Mastery, Harcourt, Houghton Mifflin, Scott Foresman, Success for All. Over 30,000 students were included in the analysis. Students were randomly selected from participating schools. The dependent measure was Oral Reading Fluency, assessed with DIBELS passages at four times during the school year. Growth differed by grade level and curriculum. The authors summarized the results (p. 209) “Overall, students in the Reading Mastery curriculum demonstrated generally greater ORF growth than students other curricula. Also, they more frequently met or exceeded benchmarks for adequate achievement in first, second and third grade.” The effect size for Reading Mastery versus other curricula in first grade was .44. (Copyright © 2011, National Institute for Direct Instruction (NIFDI). All rights reserved).