There is great enthusiasm in Philadelphia and in districts across the country now for "data-driven decision-making" -- using the information from assessments of student learning to guide plans for what to teach and how to teach it. The core curriculum has been aligned with state standards in different content areas, and the mandated tests are aligned to measure how well students are mastering those standards. The notion of using data for instructional improvement has an appealingly logical quality to it: educators get data, educators examine data to see where their students are strong and weak, and educators modify what and how they teach so that students learn more. The research on school change however, suggests that the translation of data into increased student achievement is a challenging process. It shows that teachers and principals need easy and timely access to information that is well-organized and engagingly presented. They need the skills to analyze information and to formulate questions about their students' learning. They need to believe that the information is not only accurate, but is also a good and fair representation of what their students know and are able to do. Additionally, educators need the time to have conversations about what their students are and are not learning. School cultures need to be trusting and open environments where educators feel safe enough to be honest about what's working and what's not in their classrooms and courageous enough to make needed changes. A few web-based resources are described here that store individual student data on a variety of indicators including attendance, report card marks, standardized test scores (including not only TerraNova and PSSA, but also a variety of reading assessments and the benchmark tests for the core curriculum) are presented. School District officials are enthusiastic and believe that data use will continue to help students move to new levels of achievement. It will be important to watch whether this happens and to identify the practices and tools that help principals and teachers make use of the data that is quickly becoming available to them.