The purpose of this study is to determine the difference in the mathematics academic achievement of students when teachers engage in Data Teams, a continuous improvement process, and when they do not. Additionally, this study will examine differences in mathematics academic achievement of students by ethnicity, gender, and socio-economic status when teachers engage in Data Teams and when they do not. The primary features of the Data Teams process are formative assessments, differentiated instruction, monitoring and feedback, and teacher collaboration. The instrument that will be used to determine the mathematics academic achievement of students is the Texas Assessment of Knowledge and Skills (TAKS). TAKS data for current twelfth grade students will be collected from the 2008, 2009, 2010, and 2011 school years. The 2008 TAKS data will serve as baseline data as teachers did not engage in the Data Teams process during the 2007-2008 school year. [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.]