Cost-effectiveness with multiple outcomes.

In a large number of situations, activities in health care have to be measured in terms of outcome and cost. However, the cases where outcome is fully captured by a single measure are rather few, so that one uses some index for outcome, computed by weighing together several outcome measures using subjective and somewhat arbitrary weights. In the paper we propose an approach to cost-effectiveness analysis where such artificial aggregation is avoided. This is achieved by assigning to each activity the weights which are the most favourable in a comparison with the other options available, so that activities which have a poor score in this method are guaranteed to be inferior. The method corresponds to applying Data envelopment analysis, known from the theory of productivity, to the context of health economic evaluations. The method is applied to an analysis of the cost-effectiveness of alternative health plans using data from the Medical Outcome Study (JAMA 1996; 276: 1039-1047), where outcome is measured as improvement in mental and physical health. 2004 John Wiley & Sons, Ltd.