Continuous test norms
For (cognitive) tests for children and adolescents it is important to avoid the bias that occurs with traditional cohort norms when a testee moves from one norm table to the next one; for popular IQ tests these biases are commonly 3-4 IQ points, but may occasionally reach 10 IQ points. By using continuous norming, norms score can be calculated at the level of age in days and the norm table transition gaps are avoided. I constructed such norms for the Cattell Fluid Intelligence Test (CFT 20-R) for the UK, Netherlands, Sweden, and Norway, the d2 and d2-R (Netherlands), the Adaptive Behavior Assessment System (ABAS-3) for Sweden, Denmark, Finland, and the Netherlands, and multiple school progress tests for Boom testuigevers (Netherlands).
Other tests and questionnaires
Other tests and questionnaires I was involved with in developing or adapting include: the Hogan Personality Inventory, the Hogan Development Survey, the Randstad Vocational Interest Test, the Gastrointestinal Quality of Life Index, the Medical Outcome Studies (SF-20), the Dutch Eating Behavior Questionnaire (DEBQ-C), the Emotion Awareness Questionnaire (EAQ), and the Motivation at School Questionnaire (LMT).