Despite a decades-long battle to reform American education, we are still failing to prepare all American students for success in a complex, global marketplace. Increasingly, we have turned to assessment as the tool that will help us fix American education, and yet the ever more elaborate systems of standardized testing we have designed have not done the job. In an age when testing is used to create scores and rankings, enforce standards, and secure accountability, Edmund W. Gordon shows how we can use it instead to support teaching and develop students' competencies. Between 2011 and 2013, Gordon chaired an interdisciplinary commission of scholars and thinkers, who connected transformative research and ideas on learning, teaching, measurement, the nature of tests, intelligence, capability, technology, and policy. Uniting the Commission's work with his decades of experience in the fields of education and psychology, Gordon shows how to create assessments that are integrated into education, serve the needs of teachers and students, and allow learners to flourish. He lays out this vision: when assessment focuses on improving teaching and learning rather than measuring what students have learned, we can achieve excellence in education for all students in America.