Bas holds master degrees in Clinical Psychology (2001) and Philosophy (2003), both from the University of Amsterdam, and earned his PhD on methodological aspects of Quality Adjusted Life Years from the Amsterdam Medical Centre (2007).
He has worked as an independent consultant and researcher in health economics and outcomes research since 2008. He is part-time senior scientist at the business office of the EuroQol Research Foundation, and affiliated to the ErasmusMC, Rotterdam. He specializes in the measurement and valuation of Patient Reported Outcomes, psychometrics and biostatistics. He has experience in the clinical areas of oncology, neurology, dermatology and diabetes.
He published more than 75 articles on health-related quality of life measurement and valuation, applied and methodological studies in patient reported outcomes, psychometrics and methodology. He co-authored the handbooks ‘Self-Reported Population Health: An International Perspective based on EQ-5D’ (with Agota Szende and Juan Cabases) and ‘Methods for Analyzing and Reporting EQ-5D Data’ (with Nancy Devlin and David Parkin). He was a lead investigator in the development of the EQ-5D-5L and interim value sets for the EQ-5D-5L, and was a co-chair for the EuroQol Group’s Populations and Health Systems Group (2014-2023). He was a principal investigator of the Swedish PROMs program (2017-2021), a program which supports the use of patient-reported measures within the Swedish National Quality Registers (NQR), and is member of the editorial board of PLOS ONE.