The disability weights are derived from presumably representative answers to questions of the type: "how many outcomes of one kind (e.g. saving girls from premature death) do you consider equivalent in social value to y outcomes of another kind (below-knee amputation for girls who have suffered mine explosions)"? The method used to assess these social preferences from a representative sample of persons is a deliberative person-trade-off technique. [Murray, 1996 ; Nord, 1994; Nord, 1995].