He has over 30 years experience in the methods and practice of economic evaluation in health care and has been involved in a large number of studies including: international drug trials, evaluations of national programmes for heart and liver transplantation, screening for breast cancer and abdominal aortic aneurysms, evaluation of pilot projects such as the picture archiving and communication system (PACS) at Hammersmith Hospital, assessments of the impact of medical audit and other organisational changes. He has been a member of the Appraisal Committee of the National Institute for Health and Clinical Excellence and has advised most of the major pharmaceutical companies.