Perspectives on the assessment of need.

The new arrangements for the NHS require that health services are procured which meet the identified needs of the population. To reach an agreed understanding of those needs a number of different perspectives must be reconciled--the nature of disease at a population level versus the individual's perception of illness, the general manager's desire to estimate what level of a particular service to provide versus the medical concept of packaging different services to meet a need, the clinical and epidemiological tendency to consider disease processes rather than unclassified symptomatology, and the balance of need and demand. These conflicts are described in relation to ischaemic heart disease. The task is one of complexity, challenge and opportunity.