The purpose of this ex post facto study was to analyze archive data to investigate the effects of Read 180, a computer-based supplemental reading intervention, on students' academic achievement for the academic school year 2011-2012. Further analyses examined if influences existed in variables such as grade level, gender, and ethnicity of the students in grades 6 to 8 enrolled in a large urban school district. The data obtained on the control group used for comparison were for students in grades 6 to 8 who had participated in the traditional literacy academic intervention support (AIS) class in place of the Read 180 Program. The quasi-experimental research design utilized a quantitative, comparative analysis of pre- and post-test Scholastic Reading Inventory Test (SRI) scores for 228 students in grades 6 to 8 to determine academic growth. Data were obtained regarding 114 students enrolled in the Read 180 Program, and data for the control group pertained to 114 additional students enrolled. An analysis of covariance (ANCOVA) was implemented to ensure equality of SRI pretest scores. The findings indicated statistically significant differences did not exist for students in grades 6 and 8. However, a significant difference was found for students in grade 7. Regarding the exploratory questions, no statistically significant differences were found for males, females, or ethnic groups among students in grades 6 to 8. This study's results may help educators make educated, cost-effective decisions when purchasing intervention programs to help improve their students' literacy skills. [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://www.proquest.com/en-US/products/dissertations/individuals.shtml.]