Education reform is inevitable; however, the journey of reform must ensure that educators are equipped to meet the diverse needs of all children within the classrooms throughout. Data-driven decision making is going to be the driving force for making that happen. This mixed model research was designed to show how implementing data-driven instruction improves teacher effectiveness and teacher collaboration. The purpose of this study was to stimulate positive organizational and systemic change using data-driven instruction. It was to explore the process of integrating formative and summative assessments, while assessing the benefits and challenges of implementing data-driven instruction. The researcher explored how data was gathered and analyzed, and how its usage correlated with teacher-effectiveness and teacher-collaboration. The intent was to examine the level of satisfaction of teachers as it relates to knowledge and training in the area of data-driven instruction, and advance the use of assessment data in the classroom. [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.]