The purpose of this study was to determine whether the students who attended one elementary school in Miami-Dade County, Florida, run by The Edison Project (Edison Schools, Inc.) made greater academic progress than comparable students who attended other district schools. The paper provides a longitudinal examination of the students' academic achievement during the school's first 3 years of operation, 1996-1997 through 1998-1999. The study also extends the range of statistical techniques commonly used in program evaluations. Hierarchical linear modeling (HLM) was used in an individual growth curve analysis to examine the students' achievement in reading and mathematics. Project and control groups' reading and mathematics scores on the Stanford Achievement Test were compared. Two panels of students in the project school were compared. Panel A was comprised of 114 students initially enrolled in grade 2, and Panel B of 159 students initially enrolled in grade 3. Using stratified random sampling, equal numbers of students who attended other district schools were selected as control groups. Analyses were completed in reading and mathematics. Results of the HLM analyses indicate that significant levels of growth were achieved across the 3-year period in both subject areas for all groups of students. In reading, there were no statistically significant differences between project and control groups that could be attributed to group membership, but in mathematics the results were less consistent. In Panel A, no significant source of between-group variation was identified. In Panel B, however, the rate of growth in mathematics over time was greater for project students than for control students. This was the only statistically significant difference attributed to group membership across the analyses. After 3 years of instruction through the Edison model, reading and mathematics performance levels did not differ significantly from those of students in other district schools. (Contains 6 figures, 12 tables, and 30 references.) (SLD)