Decision analysis consists of a set of tools supporting and handling structured evaluation. Such methodology is widely used for the economic evaluation of health care planning and programmes. This article outlines some characteristics regarding complex decision-making and shows the fundamental issues and stages considered when making decisions in an uncertain scenario (problem definition, choosing an appropriate time-frame, structuring the problem, developing a model for analysing it, selecting the best alternative and analysing sensitivity). Some criticism of this decision-making method is then made.