I studied medicine at the University of Groningen (1985), and I received a PhD (neurology / medical physics) from the University of Utrecht (1989). Since 1990, I have worked as a clinical epidemiologist in the Netherlands and the UK. I joined the School in January 2000. I collaborate with the Royal College of Surgeons of England (from 2001 to 2011 as the Director of the College's Clinical Effectiveness Unit). I also advise the Royal College of Obstetricians and Gynaecologists on research and audit since 2006. I am involved in the Public Health MSc. I am the organiser of the Proposal Development module. I also contribute to the Basic Epidemiology and Reviewing the Literature modules. In addition, I organise courses on critical appraisal of the literature and statistics for The Royal College Surgeons of England. The central theme of my research is the study of determinants of variation in processes and outcomes of surgical care ("epidemiology of the quality of surgical care"). I am involved in a number of national studies of surgical practice and outcome that are run by the Clinical Effectiveness Unit of the Royal College of Surgeons of England. 

I do similar work within obstetrics and gynaecology in collaboration with the Royal College of Obstetricians and Gynaecologists. Other topics of my research include methods for case-mix adjustment, continuous monitoring of outcomes, the usefulness of routine databases for clinical audit as well as clinical and cost effectiveness of therapeutic and diagnostic procedures. Previous work looked at the effect of the fetal environment on the development of disease later in life. Disease and Health ConditionsSaving energy never goes out of style. Meet the Nest Learning Thermostat > Even the bad guys will stop and stare. Nest Cam Outdoor > See your home.Nest Cam Indoor > The smoke alarmother alarms look up to. Nest Protect > Build your connected home at the Nest Store. Shop now > Oh no, what happened? Check out mysteries solved with Nest Cam Outdoor. Nest Blog We’ve changed the game. On its own, a camera is just a pair of eyes. Even if those eyes are really good, security requires more than eyes.