The principles of rational choice, individual maximization, utilitarianism and market theory further suppose that the outcomes for winners and losers can be identified, compared and measured. Under these basic premises, the goal of attaining allocative efficiency can be defined according to some principle where some allocations are subjectively better than others. For example, an economist might say that a change in policy is an allocative improvement as long as those who benefit from the change (winners) gain more than the losers lose (see Kaldor–Hicks efficiency).