Charles Lewis is a distinguished presidential appointee at ETS. He received a Ph.D. from Princeton University in 1970 with a major in statistics and psychometrics. He is a member of the American Educational Research Association (AERA), the American Statistical Association, the National Council on Measurement in Education, and the Psychometric Society. He has received an award for scientific contributions to credentialing from Professional Examination Service, the ETS Senior Scientist Award, Professor of the Year Award from the Graduate Student Association of Fordham University, and the E. F. Lindquist Award from AERA. He was awarded an ETS patent (No. 5,059,127) for a Computerized Mastery Testing System. His research interests include fairness and validity in educational testing, statistical models in test theory, applications of Bayesian statistics, and generalized linear models. He is currently working on topics in test security.