A method of evaluating economic changes which puts more weight on reductions in welfare than on increases. The extreme form of this is the Pareto criterion by which nobody must lose, but less extreme forms are common. Policy-makers are well aware that resentment for injuries is more intense and more persistent than gratitude for favours. Many protectionist policies can best be justified on the grounds that they prevent losses by particular groups, regardless of the cost to other people. Where a utilitarian would favour any change which gave a larger gain to a poorer group than it caused losses to a richer one, a policy-maker with a conservative social welfare function might resist it.