Welcome to my site. I am a Professor in the Advanced Quantitative Methodology program in the UCLA Graduate School of Education and Information Studies, where I also serve as Co-Director of the National Center for Research on Evaluation, Standards, and Student Testing (CRESST). In addition, I am affliated with the UCLA Department of Psychology in the quantitative area, where I also teach and train students.

Broadly speaking, my methodological research agenda involves the development, integration, and evaluation of innovative latent variable models that have wide-ranging applications in educational, psychological, and health-related domains of study.

A key component on this agenda is statistical computing, particularly as related to item response theory (IRT) and multilevel modeling. Close collaborations with David Thissen (UNC) and Stephen du Toit (Scientific Software International, Inc.) in the past several years have led to the development of a completely new multidimensional IRT software program for item analysis and test scoring (IRTPRO).

For more information about the multilevel IRT and diagnostic classification IRT software package flexMIRT, please visit www.flexmirt.com.

I have also collaborated with substantive researchers at UCLA and elsewhere on projects examining measurement issues in mental health, substance abuse treatment, and patient-reported outcomes research.

Please go to my CV for some of my recent published research.