Cees Glas a full professor at the Department of Research Methodology, Measurement and Data Analysis, of the Faculty of Behavioural Science of the University of Twente in the Netherlands. The focus of his work is on estimation and testing of latent variable models in general and of IRT models in particular, and on the application of IRT models in educational measurement and psychological testing. He participated in numerous research projects including projects of the Dutch Ministry of Education (OCW), the Dutch National Institute for Educational Measurement (Cito, the Netherlands), the Law School Admission Council (USA) and the OECD international educational survey PISA. He serves as a member of the technical advisory committees of the OECD projects PISA and PIAAC. He will serve as president of the Psychometric Society in 2018.
Published articles, book chapters and supervised theses cover such topics as testing of fit to IRT models, Bayesian estimation of multidimensional and multilevel IRT models, modeling with non-ignorable missing data, concurrent modeling of item responses and response times, concurrent modeling of item response and textual input, and the application of computerized adaptive testing in the context of health assessment and organisational psychology.
IRT software and manuals are available at https://www.utwente.nl/en/bms/omd/employees/Employees/glas/