In 1991 the Center for Reading and Language Studies at Indiana University (Bloomington) assembled educational experts to investigate the validity of performance-based assessments for determining the achievement of high school students in reading, writing, and mathematics. The Indiana Performance Assessments that materialized from this project were subsequently used with over 5,000 students. This report describes the development of the assessments, their field trials, scoring, reliability, findings and test results, and how teachers and students responded. Of the 10 holistic assessments developed, 6 integrated reading and writing, and 4 integrated mathematics and communications skills. Given pilot testing constraints, student performance on these assessments was acceptable, and reliable increases in performance were seen from grade 9 through grade 11, with a significant increase beyond high school. The project successfully assessed over 5,000 students while conducting a survey and demonstrated that performance assessment is feasible on a large scale. The generally positive reception of the assessments indicates that both students and educators understand, or at least sense, the limited perspectives of much standardized testing, and welcome assessment in an integrated and authentic way. Results also indicate that reliability of scoring by a carefully-trained cadre is acceptable and the process quite feasible. Thirty-nine charts illustrate the discussion. (SLD)