Pathblazer is a supplemental, online intervention program that helps struggling learners in grades K-8 achieve grade-level proficiency in mathematics and reading. It offers students individualized learning progression paths with fun, motivating content that addresses skill and concept gaps. Using existing student data or results from a screener, Pathblazer immediately identifies where students are struggling and provides the targeted instruction they need to close early learning gaps. Edgenuity contracted with the Center for Research and Reform in Education (CRRE) at Johns Hopkins University to estimate the impact of Pathblazer on student reading achievement by conducting a cluster randomized controlled trial of Pathblazer during the 2019-2020 school year in Floyd County, Georgia. The study was designed to meet the Every Student Succeeds Act (ESSA)'s "strong" or Tier 1 evidence. The analysis determined whether students in Pathblazer classrooms improved their reading more than those in control classrooms, controlling for teacher effects, student prior achievement, and other student covariates. The study also examined how teachers implemented Pathblazer, and how educators and students perceived the effectiveness and usefulness of the program. The study found that Pathblazer was most beneficial for low- and high-achieving students. For low-achieving students, Pathblazer helped fill in gaps in students' knowledge and skills. For high-achieving students, teachers believed that Pathblazer provided access to more advanced content that gifted students would not otherwise have had.