Bernie J. O'Brien BA, MSc, PhD was Director of PATH and Associate Director of the Centre for Evaluation of Medicines at St. Joseph's Healthcare, Hamilton, Ontario. He was also a Professor in the Department of Clinical Epidemiology and Biostatistics, McMaster University and Director, Clinical Effectiveness Research of the Father Sean O'Sullivan Research Centre and an Associate of the Centre for Health Economics and Policy Analysis, McMaster University.

Bernie will be remembered as an enthusiastic colleague, a spirited collaborator, a trusted mentor, and held in high regard among those fortunate enough to work closely with him.

Bernie was an outstanding teacher and researcher in the field of economic evaluation, who published more than 150 books, articles and papers. His particular fields of expertise were economic analysis alongside clinical trials, decision analytic modelling, health output measurement and valuation, statistical analysis in economic evaluation and health technology assessment.

Bernie was an excellent and avid teacher and much sought after by students of all levels of education and from around the world. He was a teacher with an infectious enthusiasm for communicating health economics concepts in an understandable, always humorous, way. His main passion was for the development of young investigators and many benefited from his mentorship and encouragement. In particular, Bernie had set up a very successful post-doctoral fellowship position to encourage young researchers to work closely with him and his group. He had the foresight to encourage not just health economists but scholars from other disciplines, such as epidemiology, that he saw as integral to successful health economic evaluation.

A close friend and colleague Michael Drummond wrote:  "When someone is taken from us in their prime, one wonders what they would have gone on to achieve had they lived. Bernie was obviously destined for a top leadership position in health economics. I imagine that he would have developed new ways to merge theory and practice. He would have also accomplished this whilst establishing a learning environment where the skills of a new cohort of young researchers were developed."

A colleague of Bernie's, Andy Briggs wrote:  "Bernie's contribution to health economics in the area of health economic evaluation is undeniable. Perhaps more importantly, however, was his infectious enthusiasm for his subject and his ability to inspire junior researchers. Those of us who knew Bernie will miss him terribly, yet it is the coming generation of health economists who have really lost out. Without Bernie, health economics will just be a little less fun."