The emphasis on using performance assessments to support systematic state-, district-, or school-wide purposes is a recent development in the assessment-reform movement. This document presents data from a 3-year case study that was designed to elucidate the status of assessment reform in United States education systems and offer recommendations for policy and future research. Researchers made visits to 16 schools during spring 1994; they revisited 7 of the sites during spring 1995. Data were derived from documents, telephone interviews, observations, and onsite interviews. Each case-study summary contains four sections: a school profile and introduction, a description of performance assessment, the context of implementation, and the use and impact of performance assessment in the school. Appendices contain a sample mathematics task; a list of essential skills for reading, writing, and mathematics in grades 9-12; and mathematics rubrics. (LMI)