In response to the greatly increased use of statewide high stakes testing, the National Research Center on the Gifted and Talented at the University of Virginia developed differentiated authentic assessments for middle school classroom use that embodied key concepts, principles, generalizations, and processes in the disciplines of English/language arts, mathematics, science, and social studies. A small scale study of the psychometric attributes of the authentic assessments was also conducted. Results provide evidence that authentic assessments can be developed to provide reliable and valid information about student learning and an accurate assessment of students' success in achieving academic learning standards, with positive responses of both teachers and students to the authentic assessment experience. Individual chapters address: (1) effects of high stakes testing; (2) content and principles for the development of authentic assessment tasks; (3) psychometric attributes of the authentic assessments; and (4) teachers' and students' responses to authentic assessments. Appendices provide five examples of authentic assessment tasks with scoring rubrics. (Contains 31 references.) (DB)