The purpose of this longitudinal quantitative study was to determine the academic impact of the Leader in Me process on a public elementary school in Delaware as it relates to growth in reading and mathematics using the Measures of Academic Progress. This longitudinal case study focused on determining if a significant statistical difference existed between the expected end of year RIT score and the actual end of year RIT score over a five-year period. Research questions focused on the impact on reading and mathematics achievement for students who attended a Leader in Me elementary school as measured by Measures of Academic Progress. Beginning and end of year RIT scores were collected ex post facto for each year from the 2013-2014 school year through the 2017-2018 school year. Using the predetermined RIT growth scores set by NWEA based on individual student benchmark scores from the beginning of the year, a descriptive statistic score was calculated to establish the mean. This mean was used as the test value in a one sample "t"-test and compared to individual student's actual growth at the end of each year. A statistical significance was determined in two years out of the five in reading and four years out of the five in mathematics. Although the results are inconclusive, benefits were evident in the data. The implications from the results of this study should be used in conjunction with future research to determine the impact the Leader in Me process has on academic 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.]