The purpose of this study was to compare the mathematics achievement outcomes of 3rd grade students from some Pacific Island elementary schools that use 1 of 3 different modes of instruction: Direct Instruction (DI), Success for All (SFA), and noncomprehensive school reform (non-CSR). The need for this research stems from the large proportion of students who, year after year, perform at the lowest level of mathematics mastery on the Stanford Achievement Test version 10 (SAT 10), which is used to track adequate yearly progress. The behaviorist and constructivist theories of learning served as the theoretical framework of this study. Using a quantitative, causal-comparative design, archived data for 615 3rd graders were collected from the 2011-2012 SAT 10 mathematics subtest. Three schools from each type of instructional program were selected using cluster random sampling. The SAT 10 scaled scores for Mathematics Procedures, Problem Solving, and Total Mathematics served as the dependent variables for this study. One-way ANOVA and Tukey's posthoc test indicated that SFA students scored significantly higher than DI and non-CSR students in all 3 outcomes that were compared. DI and non-CSR students did not score significantly different from each other in any of the 3 outcomes. The results of this study contribute to positive social change by informing educators and administrators as to which instructional program results in higher mathematics achievement outcomes. Future research should examine if the SFA program outperforms the DI and non-CSR programs in other grade levels and curricular areas. Additionally, future research should examine how CSR reading programs interact with mathematics programs to influence mathematics achievement for this population. [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.]