This is the last of four articles

The constant introduction of new health technologies, coupled with limited healthcare resources, has engendered a growing interest in economic evaluation as a way of guiding decision makers towards interventions that are likely to offer maximum health gain. In particular, cost effectiveness analyses—which compare interventions in terms of the extra or incremental cost per unit of health outcome obtained—have become increasingly familiar in many medical and health service journals.

Considerable uncertainty exists in regard to valid economic evaluations Firstly, several aspects of the underlying methodological framework are still being debated among health economists. Secondly, there is often considerable uncertainty surrounding the data, the assumptions that may have been used, and how to handle and express this uncertainty. In the absence of data at the patient level sensitivity analysis is commonly used; however, a number of alternative methods of sensitivity analysis exist, with different implications for the interval estimates generated (see box). Finally, there is a substantial amount of subjectivity in presenting and interpreting the results of economic evaluations.

The aim of this paper is to give an overview of the handling of uncertainty in economic evaluations of healthcare interventions.3 It examines how analysts have handled uncertainty in economic evaluation, assembled data on the distribution and variance of healthcare costs, and proposed guidelines to improve current practice. It is intended as a contribution towards the development of agreed guidelines for analysts, reviewers, editors, and decision makers.4^–7