Background/Context: Calls for evidence-based decision making have become increasingly prominent on the educational landscape. School district central offices increasingly experience these demands. Yet there are few empirical studies of evidence use at the district level. Furthermore, research on evidence use among policy makers in noneducation settings raises questions about the models of decision making promoted by evidence-use policies, suggesting that they do not take into account key features of the interpretive process or the organizational conditions that shape how decision making unfolds. Purpose/Objective/Research Questions/Focus of Study: The central premise of this article is that only by understanding the patterns by which personnel in school district central offices actually use information, and the factors that affect this use, can we begin to understand the promise and possibilities of evidence use. We ask: What is the role of evidence in instructional decision making at the central office level? What factors shape how decision processes unfold? Research Design: We draw on data from a longitudinal case study of one midsize urban district, which we followed from 2002 to 2005. We relied on in-depth interviewing, sustained observation, and document analysis. We identified 23 decisions related to instruction that were captured in our data over the 3 years and for which we had at least three independent sources of information. We analyzed each decision using a coding scheme that was developed from prior research and theory and elaborated through iterative coding. We then used matrices to compare across decisions and to surface and investigate emerging patterns. Conclusions/Recommendations: We argue that decision making in complex organizations like school districts is centrally about interpretation, argumentation, and persuasion. These processes are shaped in crucial ways by preexisting working knowledge and practices that guide how people come to understand the nature of problems and possible avenues for solutions. They are also influenced by organizational and political factors, including the organizational structure of the central office, resource constraints, and leadership turnover. We close by suggesting implications for efforts to foster substantive and productive use of evidence at the central office level.