Many studies have been made to obtain a monetary valuation of reduced risk of death, usually given as the value of a statistical life (VSL), which is a reduction in risk corresponding to the prevention of one fatality. This paper asks whether valuation research provides a credible basis for cost-benefit analysis of safety measures. A cost benefit analysis is credible if its results cannot be criticised by reference to the valuation studies forming its basis. It is argued that a credible basis for cost-benefit analysis in this sense does not exist. The monetary valuations of a statistical life vary enormously. The enormous diversity in values is increasingly accepted by researchers working in the field as inevitable and consistent with indiv...