The purpose of this quantitative study was to investigate the effectiveness of a system-wide Response to Intervention (RTI) program on the mathematical achievement of seventh and eighth grade students. The study consisted of five district schools with a total of 502 participants. The students were identified as belonging to one of two tiers, which differed in regard to amount of intervention. The first tier (Tier 1) of students only received the regular classroom instruction while the second tier (Tier 2/3) received an additional thirty minutes of intervention strategies. The students receiving interventions, the Tier 2/3 students, were divided into two groups. One group received primarily teacher-directed instruction (TDI) as an intervention while the other group received computer-assisted instruction (CAI) as an intervention. For the purpose of this study, the CAI intervention involved the use of the commercial program, Odyssey Math. The students were benchmark tested at the beginning and end of the 2010-2011 school year using the STAR Math assessment program and also progress monitored on a regular basis. In an attempt to determine the effectiveness of the RTI program, a gain score ANOVA was conducted using the scaled scores of the two tiers from the beginning and the end of the school year. The analysis indicated that Tier 2/3 students did demonstrate greater growth than the students in Tier 1. The gain scores of the two groups of Tier 2/3 students were also used in a gain score ANOVA to measure differences in growth. An additional analysis of their mean scores was also conducted using ANCOVA. Both analyses indicated that the CAI group demonstrated greater gains. A third analysis was conducted in order to determine how accurately the STAR Math assessment program could predict student success (reaching either a Proficient or Advanced level) on the state assessment. While the STAR Math program did not accurately predict the students' level in every case, the logistic regression analysis did indicate that the program was successful in identifying struggling 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://www.proquest.com/en-US/products/dissertations/individuals.shtml.]