This research was a mixed-methods study investigating how teachers in northeastern West Virginia use student data to drive their instructional decisions. This study also investigated teachers' perceptions of the data use on their instruction, their students, and themselves. Data collection for this research included both a cross-sectional survey and semi-structured, one-on-one interviews. Findings included a general positive attitude toward data use and a strong perception of positive impact upon instruction, students, and teachers as practitioners. Teachers described six major uses of data, including: 1) determining whole group lesson focus within the standards, 2) determining whole group pacing, 3) determining student groupings for small group instruction, 4) determining small group lesson focus within the standards, 5) determining small group pacing, and 6) determining recommendations for additional instructional support. It was noteworthy that participants in this study reported strong supports in their schools and districts including supportive leadership, regular collaboration, access to technology, and a data-driven culture. [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.]