This excellent book summarises the literature on managed care, as it has been practised in the US, and attempts to extract results and conclusions that could be of benefit to the NHS. As the authors detail, this is a far more difficult project than it might seem at first.

The basic problem is that managed care has no single definition, refers to no single method of financing or delivering healthcare, and perhaps most significant, is constantly in a state of organisational flux. The populations enrolled in managed care plans are therefore difficult to standardise, and the time that each study covers may not necessarily be long enough to show long-term results. For example, it is easy for a managed care plan to reduce hospitalisation and substitute ambulatory care, since that is the fundamental operating principle of managed care, but it is possible that over a long period of time patients treated in this manner may require more hospitalisation than those who have been in a fee-for- service environment. While short-term costs may be less, there may be a long-term increase in spending.

To reach meaningful conclusions about whether managed care works (that is, does it save money or promote better health outcomes than other methods of providing care?), we need some standardisation of what is being measured, for how long it is being measured, and how it is being defined.

Unfortunately, this turns out not to be very easy to do with managed care, and it is a tribute to the careful scholarship of the authors that they are able to derive conclusions at all.

While no overall conclusion is drawn about managed care from the studies that the authors have reviewed, I would assess the evidence as generally mixed. I found the summary tables that the authors have included to be of great use and great ease in extracting what conclusions can be made. The authors make clear that the lack of random controlled trials makes rigorous analysis difficult. They conclude that the more strictly managed models in the US, (such as the Kaiser system), which do not permit out- of-network utilisation, have lower rates of hospital and ancillary service utilisation. However, despite these results, this type of managed care is rapidly being phased out in the US.

I found the discussion of the use of managed care techniques in the NHS to be of particular interest. The literature on the use of specific aspects of managed care, such as utilisation review and physician profiling, may be of great use in enhancing the efficiency of another system. While the authors note that there are significant differences in the way and the purpose for which managed care techniques are used in the NHS, they do not stress the fundamental difference of increasing efficiency in a universal system versus increasing private gains in a system without universal access. This is an important distinction since, in the US, managed care is a way of life and a gestalt rather than simply being a method of controlling utilisation of health services as it is in the NHS.

Very useful is the authors' discussion of the value of randomised clinical trials on policy options as well as medical procedures, and the differences between utilising information from other countries and better understanding the distinctions between the healthcare systems of different countries. It is not the easiest book to read, with rather drab writing, but the reader will get a much better appreciation of what managed care can and cannot do as reported in the scientific literature.

HOWARD BERLINER

Associate professor and chair, health services management and policy, New School for Social Research, New York.