This case study of one school district examined how school leaders use student performance data and technology-based data analysis tools to engage in data-informed decision-making for continuous improvement. School leaders in this context included leaders at the district, school, and classroom levels. An extensive literature review provided the framework for this study including Brunner, Fasca, Heinze, Honey, Light, Mardinach, and Wexler (2005), Knapp, Swinnerton, Copland, and Monpas-Huber (2006), Mandinach, Honey, Light, Heinze, and Nudell (2005), Mandinach, Honey, and Light (2006), Marsh, Pane, and Hamilton (2006), National Education Technology Trends Survey (2005, 2007), among others. Though data-informed decision-making is not a new concept in industry or education, the data-reporting demands of the No Child Left Behind Act has fueled districts' investments in technology and data analysis tools. The case study employed a mixed data collection approach. Qualitative data were collected through interviews of 12 leaders (1 superintendent, 1 technology leader, 2 principals, 2 curriculum coordinators, 2 instructional specialists, and 4 lead teachers), and review of district documents. Quantitative data were collected through an online survey of the teachers in the district to validate or triangulate portions of the interview data. Qualitative data were analyzed at various levels of descriptive analyses, in which codes were generated, organized, and grouped into analytical categories. Findings showed that leaders used various forms of data to make various types of decisions. The district provided the tools and training. In addition, leaders' organizational roles or levels impacted the forms of data they used and the types of decisions made. Organizational roles also impacted leaders' perceptions of which environmental factors (political, economic, cultural, and technological) influenced their use of student data to make decisions. A culture of data use was more prevalent among accountability workgroups such as English, math, and science teachers--evidence that political forces influence teachers' data use. Cultural and human resource capacities were developed through professional learning communities and early release days. Teachers had time but wanted more time. District Y is modeled after best practices. Recommendations were made for all stakeholders as well as the government and schools of education. [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/en-US/products/dissertations/individuals.shtml.]