In a policy marked more by controversy than consensus, medical schools in the United States have joined the United Kingdom in embarking upon the largest expansion in the training of doctors in more than a generation. In this week's BMJ, Weiner outlines the rationale for this initiative while questioning the Association of American Medical Colleges' evidence to support such an expansion.1 Given the differences between the US and other countries within the Organisation for Economic Cooperation and Development, can the US healthcare system provide any generalisable policy lessons?

The question of whether there is or will be a surplus or shortage of doctors is usually answered by projecting today's healthcare system into the future. Using this method the answer is simple—because of population growth and ageing we need more doctors. However, when we consider how to improve the health and wellbeing of growing …