Dimiter M. Dimitrov is Professor Emeritus at George Mason University, USA, and Senior Psychometrician at the National Center for Assessment in Riyadh, Saudi Arabia. His areas of expertise include assessment, psychometrics, and advanced quantitative research methods in education, psychology, and related fields. Dr. Dimitrov earned a PhD in mathematics education from the University of Sofia, Bulgaria (1984), and a PhD in educational measurement and statistics from Southern Illinois University, Carbondale, USA (1995). His professional work and publications have received international recognition. Dr. Dimitrov has served as president of the Mid-Western Educational Research Association in the USA, program chair of the SIG Rasch Measurement of the American Educational Research Association (AERA), editor of Measurement and Evaluation in Counseling and Development, and member of the editorial board of numerous other professional journals in the field of educational and psychological measurement. His most recent research efforts resulted in the development of the D-scoring method of measurement (DSM) as a unified framework of classical and latent scoring and analysis of test data. Dr. Dimitrov is multilingual and has lectured and published professional work in English, Bulgarian, Russian, and French.