From an economic point of view, value of life refers to the price individuals are prepared to pay to get longer expected lifetimes. Similarly, public decision-makers face choices between programmes aimed at reducing risk which must reflect what society is willing to pay for such a reduction. To capture this collective value, the notion of statistical value of life has been defined and is used ex ante, before the decision is taken and therefore without knowing who will benefit from the risk reduction it entails. The purpose of this paper is to review the methods used to provide an estimate of this kind of collective value, to show that it promotes an ethical approach to public decision-making and to compare its use in two fields of application: transports and health.