This text employs a somewhat “traditional” approach to the study of educational tests and measurement so that teachers will understand essential psychometric concepts and be able to apply them in the classroom. The principles that guide the development of this text are (1) What essential knowledge and skills do classroom teachers need to conduct student assessments in a professional manner, and (2) What does the research on educational assessment tell us? This focus has resulted in a uniquely approachable, but technically accurate presentation of the material. While providing a slightly more technical presentation of the material than more basic texts, this text is both approachable and comprehensive. The text includes a gentle introduction to the basic mathematics of measurement, and expands traditional coverage to include a thorough discussion of performance and portfolio assessments, a complete presentation of assessment accommodations for students with disabilities, and a practical discussion of professional best practices in educational measurement.