  The upshot of this discussion is that in conditions of scarcity, there is no uniquely defensible way of spelling out the principle of distribution according to need. We face conflicting imperatives: to meet as many needs as possible, taking into account how much each costs to satisfy, and to preserve comparative justice by ensuring that people whose needs are similar are treated in the same way. This can be presented as a trade-off between efficiency and justice, but since as noted earlier we are often required to meet needs as a matter of justice, it can also be seen as a clash between non-comparative and comparative justice.