 First, some employ traditional cost-benefit analysis and seek to derive the “expected value” of different scenarios by combining the probability of each state of affairs and its value and then choosing that policy with the greatest expected value (Broome 2012: 120–132). Fleurbaey et al. (2019: 97–100) provide an excellent short analysis of this approach and variants of it. Some query the validity of the “expected value” approach on the basis that our understanding of the future is so imperfect that we lack reliable probabilities (Gardiner 2011: 261–263; though see Broome 2012: 127–129).