Based on the PRA, a risk–benefit analysis has been performed. It shows that the cost of life-boats would be economically indefensible.
Because of the low probability of an accident, the expected cost per life saved by the life-boats is very high, say above 1000 million dollars, way above what society at large is prepared to pay for a life saved in other areas such as that of road traffic. The risk–benefit analysis therefore clearly shows us that the ship should not have any lifeboats.
How should the naval engineer respond to this proposal? Should she accept the verdict of the economic analysis and exclude lifeboats from the design?
Our proposal is that a good engineer should not act on the risk–benefit analyst’s advice in a case like this.
The reason should now be obvious: It is possible that the calculations may be wrong, and if they are, then the outcome may be disastrous.
Therefore, the additional safety barrier in the form of lifeboats (and evacuation routines and all the rest) should not be excluded, although the probability estimates do not show it to be called for.