This book is designed to help K-12 teachers and administrators understand the nature of standardized tests and, in particular, the scores that result from them. This useful manual helps teachers develop the skills necessary to incorporate these test scores into various types of instructional decision making--a process known as "data-driven decision making"--necessitated by the needs of their students. This book: (1) Helps readers understand, interpret, and use standardized test scores to improve classroom instruction--Several specific examples are given for interpreting test scores and developing a plan to revise instruction based on those results; (2) Offers activities for application and reflection--Follow-up activities and discussion points are provided for experienced and preservice teachers across K-12 grade levels; and (3) Presents successful case studies--The author includes interviews with classroom teachers, building administrators, and district-level administrators who have successfully engaged in a process of incorporating test scores into decision making. Following a preface, this book is divided into four sections. Section 1, Overview of Standardized Testing: Concepts and Terminology, presents: (1) What Is "Standardized" Testing?; (2) The Importance of Standardized Testing; and (3) Standardized Test Administration and Preparation. Section 2, Standardized Test Scores and Their Interpretations, continues with: (4) Test Reports; (5) Criterion-Referenced Test Scores and Their Interpretations; and (6) Norm-Referenced Test Scores and Their Interpretations. Section 3, Using Standardized Test Scores in Instructional Decision Making, contains: (7) Group-Level Decision Making; (8) Student-Level Decision Making; and (9) Value-Added Analysis and Interpretation. This book concludes with Section 4, Case Studies: Interviews with Teachers and Administrators. A glossary; list of references; and an index are also included.