Accountability has pushed principals to use data to drive and inform decisions in schools to positively impact student achievement. Research has shown that principals are the second most important impact on student achievement, second only to teachers. Principals who can lead change in schools based on data driven response have a positive impact on student outcomes. The purpose of this analysis is to investigate the relationships between principal beliefs on data driven decision-making, school demographics, principal characteristics, and student achievement. The research design of this study uses quantitative research methodology. This was a correlational design study through an online survey that went to all public high schools' (defined as schools encompassing grades 9-12 only) principal in Florida. The survey was to capture the beliefs of principals on data driven decision-making. Using the Baron and Kenny model (1986) along with the Preacher and Hayes model (2009), the correlation was determined between the predictor variables (school demographics and principal characteristics), the mediator variables (principal beliefs regarding data driven decision-making), and the outcome variables (student achievement). School demographics were defined as student population at school, percent economically disadvantaged students, and percent minority students. Principal characteristics were defined as total number of years as a principal and number of years as a principal at current school. Student achievement was defined as English Language Arts (ELA) achievement, ELA gains, math achievement, and math gains on the Florida Standards Assessment (FSA). Several multiple regression analyses were performed to ascertain any relationship between the antecedent, mediator, and outcome variables. The bootstrapping method of analysis designed by Preacher and Hayes was also performed. Principals continue to believe in DDDM and the potential it has to positively impact student achievement. Principal beliefs regarding data driven decision-making does not mediate the effect of school demographics and principal characteristics on student achievement. Principal beliefs regarding data driven decision-making does have an indirect effect on student achievement. Specifically, principal beliefs regarding collaboration among teachers using data driven decision-making has a correlation to student achievement. Principals should lean into teacher collaboration and develop teacher teams that focus on improving instruction through data driven decision-making strategies. In addition to belief in data driven decision-making, principals need to find ways, such as work closely with teachers to improve instructional strategies, to reduce the effects of school demographics and principal characteristics 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.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]