His research focuses on methods of patient-reported outcomes and quality-of-life measurement, and the intersections of spirituality, religion, culture, and other sources of diversity in various health care contexts. He has a particular methodological interest in the use of latent variable mixture modeling for examining sample heterogeneity with respect to individuals' self-reports about their health status and quality of life. He is a member of the International Society for Quality of Life Research and the International Society for Quality of Life Studies.