Edited by M Schaud. (Pp 129; price not stated). Amsterdam: IOS Press, 1999. ISBN 0-9673355-2-3.

• Schaud M
• editor Comparison and harmonisation of denominator data for primary health care research in countries of the European Community

Several countries in the European Community have developed sentinel networks for the surveillance of morbidity, particularly communicable disease, in primary care. This book compares the ways the denominator is derived for different networks and ways that the denominators can be harmonised to allow international comparisons of disease frequency.

The book describes the work of the European Denominator Project, which was funded between 1994 and 1996. The collaborators came from Germany, Belgium, France, the Netherlands, and the United Kingdom. The different health care systems in these countries, affect the frequency with which patients consult, and more importantly the available information from which the denominator populations covered by the sentinel practices can be estimated.

After the introduction, the first two chapters provide an overview of different ways of determining the denominators for sentinel practices. These chapters have appeared previously in this journal.¹ The next two chapters describe the actual ways the denominator are derived for the sentinel systems of the collaborators' countries and the extent to which the doctors and patients involved in the sentinel practices are representative of the population at large. There follows a slightly incongruous literature review of the factors affecting healthcare utilisation. The final chapters cover comparisons between the sentinel networks for different conditions, ways of estimating the total population from the population consulting (estimation of the “zero class”) and potential ways of harmonising the denominators of the different sentinel systems.

The authors conclude that the only realistic denominator for international comparison at present is the “yearly contact group” (patients consulting during the year), which can be used to estimate the underlying denominator population of the sentinel practices.

Although the area covered by this book is not as wide as its title suggests, it does provide a useful guide to a practical problem.