Book excerpt: With the new federal law, No Child Left Behind, there is ever increasing pressure on schools to be accountable for improving student achievement. That pressure is taking the form of focused efforts around data-driven decision making. However, very little is known about what data-driven decision making can really tell one about improving achievement nor is there a full explanation available about what it really takes to do this work. The few examples that do exist, while proposing to get at some of these issues, make huge assumptions about educators' knowledge base and available resources necessary for success. In this book, Philip Streifer fills the gaps by laying out how this work can be done and then explains what is knowable when one actually conducts these analyses and what follow-up steps are needed to make true improvements. He provides readers with a comprehensive understanding of what data-driven decision making can and cannot tell educators about student achievement and addresses the related issues for leadership, policy development, and accountability. Senior level district administration for policy development, school level administrators who have to put policy into practice, and graduate college professors teaching data-driven decision making will find this book most useful.