 The process of dealing with risks is often divided into three stages: risk assessment, risk evaluation and risk management. Of these, the second is most obviously ethically relevant. However, risk assessment already involves value judgments, for example about which risks should be assessed in the first place (Shrader-Frechette 1991). An important, and morally relevant, issue is also the degree of evidence that is needed to establish a risk. In establishing a risk on the basis of a body of empirical data one might make two kinds of mistakes. One can establish a risk when there is actually none (type I error) or one can mistakenly conclude that there is no risk while there actually is a risk (type II error). Science traditionally aims at avoiding type I errors. Several authors have argued that in the specific context of risk assessment it is often more important to avoid type II errors (Cranor 1990; Shrader-Frechette 1991). The reason for this is that risk assessment not just aims at establishing scientific truth but has a practical aim, i.e., to provide the knowledge on basis of which decisions can be made about whether it is desirable to reduce or avoid certain technological risks in order to protect users or the public.