His research focuses on assessment and its implications in science education, including applications of Rasch measurement models and alignment analyses for assessments and standards. Previous affiliations include the National Institute of Education Singapore (NIE), U.S. National Science Foundation (NSF), and Westat. He holds a Ph.D. in Science Education from the University at Buffalo S.U.N.Y. and a B.S. in Mathematics and Physics from the University of Redlands.