Testwise: Understanding Educational Assessment offers a 360-degree guided tour of its subject. Both volumes in this comprehensive two-volume set explore different aspects of investigating what students have learned. To set the scene, Volume One highlights recurrent themes and the contemporary context. With roots in both academic traditions and the natural sciences, today's achievement testing reaches beyond the classroom to figure in policies aimed at educational reform and societal change. How do the ways in which we assess learning reflect values in our culture? What roles do citizens, educators, government officials, and measurement professionals play? Against this background, Volume One then lays out the fundamental principles in assessment. As the central chapters explain validity, reliability, fairness, and the language of scores, they illuminate key challenges and difficult tradeoffs associated with matters of technical quality. In helping the reader understand current issues in testing and evaluate actual tests, Testwise also puts assessment of learning in a new light. It is a process of critical thinking, reasoning from evidence, and defining the goals of education.