Allan Cohen is the O.C. and E.P. Aderhold Professor of Research Methodology, Department of Educational Psychology, and Director, Georgia Center for Assessment. Dr. Cohen's research involves examining methodological issues in educational measurement primarily with respect to applications in test design and development. Most of his work has focused on (1) problems in the construction and maintenance of achievement tests, including equating, detection of item bias, and estimation of model parameters under item response theory, (2) problems regarding standard setting, particularly for performance-type tests, and (3) investigating new methods for better understanding the test taking behaviors of examinees, especially in the context of multivariate and latent variable models. In addition to his own research, he collaborates on problems requiring statistical expertise in psychometrics.