John Deffenbaugh's article on commissioning is a majestic triumph of hope over experience and evidence.

A recent review of international experience I have undertaken has shown that in no healthcare system is commissioning done to world class standards.

This is because commissioning healthcare is inherently difficult and it explains why organisations that both commission and provide care are able to achieve very high levels of performance.

There is now mounting evidence of the benefits of clinically integrated systems of care in which physicians are empowered to bring about service improvement. In these systems, GPs work closely with specialists and other clinicians to provide high quality care to patients.

A key feature of clinically integrated systems is that they create incentives for multispecialty medical groups to keep patients healthy, provide care closer to home and ensure that hospitals are used only when necessary and appropriate.

If the NHS really is to move from good to great, the Darzi review needs to create a framework that will enable clinically integrated systems to develop in future.

Chris Ham, professor of health policy and management, health services management centre, Birmingham University