PhD. In Statistics from K. U. Leuven, Belgium (2007). He was a post-doctoral fellow at the Measurement Center, MIDE UC. Currently, he is Associate Professor at the Department of Statistics, Pontificia Universidad Católica de Chile. His main research interests are psychometric models, Item response Theory, generalized linear mixed models, models with latent variables, test equating. As a leading researcher in equating, he recently published a book with Marie Wiberg: Applying Test Equating Methods Using R.