More high school students are taking the ACT and more students are taking it at an earlier age. States such as Missouri are now testing all public and charter school students during their junior year to use the ACT as a formative assessment to drive discussions about student schedules, plans of study, and course offerings. With more data from more ACT tests, it is critical that districts, schools, and students consider what courses at the high school level translate into more college and career ready (CCR) graduates. The purpose of this quantitative quasi-experimental study was to determine if there was a statistically significant difference in final ACT math sub scores between students who took a specific upper-level math course above Algebra II during their senior year. Additionally, it focused on students whose baseline ACT math sub score taken their junior year was below the CCR recommended level of 22 as set by ACT to determine college readiness. Statistical analysis was conducted to determine if there was relationship between specific upper-level math course completion and ACT math sub score. The methodology used accessed student baseline ACT test results from their junior year, and examined the effect of student high school upper-level math course completion. The sample for this research study consisted of the 1,311 students from a large, suburban Missouri school district who had graduated from high school during 2015-2016 academic school year. The results determined that there was a statistically significant difference between students who took College Algebra compared to students who took Statistics. For students with a baseline April 2015 ACT below the ACT recommended CCR level of 22 in math, there was no statistically significant greater mean ACT math sub score for students enrolled in any class between the groups tested. [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.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]