School leaders must determine the most efficient and effective means of complying with national, state, and local policies. Administrators determine methods to meet the needs of all stakeholders. School leaders in Oklahoma selected school improvement techniques to assist with improving student performance. This causal-comparative study addressed this issue by examining the effectiveness of building level administrator's decision to adopt Marzano school reform strategies and the impact that the improvement program had on student achievement as indicated by state and national assessment scores. The study used a nonexperimental quantitative research design to analyze descriptive data. This study analyzed data from two high schools and the respective feeder middle schools in an urban area of Oklahoma from 2009-2011. The two schools have similar demographic characteristic in relationship to gender, ethnicity, percentage of exceptional learners, and socioeconomic status, Study groups consisted of 250 students from each of the schools for a total of 500 students. An analysis of covariance test used eighth-grade reading scores as a covariate to control for differences among assessment scores of learners who attended an institution that adopted either standards-based instruction or school improvement strategies. Repeated ANOVA measures calculated differences between ACT mean scores of students in both groups. All tests used a 0.05 level of significance. This study determined that Study results imply that there is a statistically significant difference in ACT or national mean test scores for students in a school in which the administrator adopted Marzano school improvement strategies and those who have standards-based instruction. Data analysis did not show a significant difference in mean scores on state administered End-of-Instruction assessments. Scores in 2010 had the greatest variation. An administrator adopting Marzano school improvement techniques does not appear to have a significant or positive influence on student achievement. [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.]