Sandra Mathison is a Professor of Education at the University of British Columbia, Canada. She has been conducting evaluations, primarily in educational settings, for more than 25 years. She began her career as an internal evaluator at a Canadian community college and has subsequently conducted dozens of external evaluations and served as the Director of Evaluation for the University of Chicago School Mathematics Project for three years. Over these many years and through these many opportunities to do and study evaluation, she has developed an interest in and contributed to evaluation through