This program evaluation of the Early Intervention Program reduced class-size model was used to provide evidence about the quality of implementation and how the model was used to increase reading achievement for students. This study used a mixed-methods approach to analyze student achievement data and teacher perception data. The qualitative data consisted of an analysis of the STRA pre- and post-test scores through descriptive statistics and a paired t-test. Qualitative data was collected through teacher and administrator interviews and a thematic analysis was conducted. Trends in explanations and/or contradictions were analyzed when considering the quantitative and qualitative data together. Through this analysis it was determined that reading achievement did increase between the pre- and post-test and that all students showed statistically significant growth. In addition, teacher perceptions of the program were positive. The factors that were mentioned that could have contributed to the success of the program included increased differentiation, more time spent on academic instruction, and stronger relationships between teachers and students. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]