The authors describe the significant contributions of Robert Ebel to educational measurement theory and its applications. A biographical sketch details Ebel's roots and professional resume. His influence on classroom assessment views and procedures are explored. Classic publications associated with validity, reliability, and score interpretation are described in terms of their contributions to the field and their relevance to current practice. An analysis of the diversity of Ebel's contributions over his career projects a model of "psychometric statesman" for contemporary measurement specialists to emulate.