The researcher employed two designs to address the research question for this particular study. This quasi-experimental non-equivalent control group study compared the math achievement of 92 eighth grade students who received Classroom Performance System (CPS)-based instruction using Peer Instruction (PI) to 76 eighth grade students who received CPS-based math instruction without PI. Posttest scores were statistically analyzed using an ANCOVA. Iowa Test of Basic Skills scores were used as a covariate. A statistic control group design was employed to examine student motivation for the same group of students under the same conditions. Student motivation data from the Instructional Materials Motivation Survey (IMMS) were statistically analyzed using MANOVA and independent sample t-tests. The results showed that eighth grade students who received CPS-based math instruction using PI had significantly higher math achievement scores. Student motivation scores were statistically higher when analyzing all four components of the IMMS together. When analyzing the components separately, two of four subscales were significantly higher for the treatment group. [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.]