Letty Koopman

Dr. Letty Koopman is an Assistant Professor at the University of Groningen's Faculty of Behavioural and Social Sciences, Department of Educational Science. Her research focuses on psychometrics, statistics, and educational measurement, particularly in item response theory, multilevel data analysis, and Mokken scale analysis. She has contributed to advancing methodologies for clustered and two-level test data, addressing challenges in scalability coefficients and model fit evaluation. Her work bridges theoretical developments with practical applications in educational and psychological testing.

Key research interests include nonparametric item response theory, inter-rater reliability, and statistical methodologies for complex data structures. Recent publications explore assumptions of two-level models and their applications in psychological and educational measurement. Koopman collaborates extensively with peers like B.J.H. Zijlstra and L.A. van der Ark, contributing to high-impact journals such as Psychometrika and Educational and Psychological Measurement.

No scientific awards or grants are explicitly mentioned in the provided texts. Her work emphasizes methodological rigor in scaling techniques and improving test instruments for pedagogical practices. She maintains an active research agenda, with ongoing contributions to quantitative psychology and educational statistics.