Klaas Sijtsma

Klaas Sijtsma is a Dutch psychologist and applied statistician. He is an emeritus professor at Tilburg University in Netherlands.

Education and career Sijtsma received his Bachelors and doctorate degrees from the University of Groningen in 1982 and 1988, respectively. His doctoral thesis was supervised by Ivo W. Molenaar. He was a faculty member of University of Groningen, the Vrije Universiteit Amsterdam, Utrecht University. He joined Tilburg University as a faculty member in 1997.

Sijtsma was President of the Psychometric Society (2010-2011), Dean of the Tilburg School of Social and Behavioral Sciences (2011-2017), Rector Magnificus of Tilburg University (2019-2020), and the chair of the Dutch Committee on Tests and Testing or COTAN (2005-2010).

Sijtsma received the Career Award for Lifetime Achievement from the Psychometric Society in 2023.

Research Sijtsma published more than 200 articles and book chapters on a variety of topics in psychology and psychometrics. He is a co-author of three books on psychometrics including a Dutch-language textbook on test theory (with Pieter Drenth), Introduction to Nonparametric Item Response Theory (with Ivo W Molenaar), Measurement Models for Psychological Attributes (with L. Andries van der Ark), and Never Waste a Good Crisis Lessons Learned from Data Fraud and Questionable Research Practices.

Books