[Utility assessment in clinical decision making].

In clinical decision analysis a quantitative value is attached to a longevity or a life quality by means of utility assessment. The actual value of the utility can determine the result of the decision analysis. In this article utility theory is briefly discussed. Four kinds of utility tests (direct scaling methods, the basic reference gamble, the time trade-off test and additive conjoint measurement) are introduced on the basis of an example and their pros and cons are discussed. It is concluded that additive conjoint measurement has the best formal infrastructure, but that the test method is not always easily applicable.