I'm an associate professor and teach at the Psychological and Mathematical Institutes of Leiden University. My research is about statistics, machine learning and psychological assessment.

• I work on decision-tree methods, because they are relatively easy to understand by non-statisticians. Here is a short interview about my work on trees (in Dutch). 

• I develop open-source software packages for the programming environment R (see links on left or GitHub). 

• My work has been published in journals like Psychological Methods, the Journal of Statistical Software, Information Fusion and World Psychiatry (see links on left or Google Scholar). 

• As Mary-Jo and the Support Vector Machines, I make music videos about statistical methods (see links on left or YouTube).