Distributional weighting and welfare/equity tradeoffs: a new approach

There are increasing calls for concrete suggestions on how to account for distributional impacts in policy analysis. Within the context of benefit-cost analysis, per se, one possibility is to apply "distributional weights," to inflate costs and benefits experienced by poor or disadvantaged groups. We distinguish between "utility-weights," intended to correct for the bias in willingness to pay caused by diminishing marginal utility of income, and "equity-weights," intended to account for the possibility that decision makers might have disproportional concern about the welfare of the poor or other disadvantaged groups. We argue that utility-weights are appropriate and necessary to maintain the legitimacy of BCA as a measure of aggregate welfare, but that equity-weights are inappropriate because they involve moral judgments that should remain in the domain of democratically accountable decision makers, and because they conflate information about both the welfare and equity impacts of policies, making it impossible for decision-makers to apply their own moral values to the assessment of tradeoffs between welfare and equity. We offer concrete suggestions regarding the application of utility-weights and the calculation of a set of metrics to provide intuitively comprehensible and useful information about, and allow decision makers to quantitatively assess the tradeoffs between, welfare and equity caused by specific policies.