Some economists have attempted to find conditions under which CBA and CEA produce
identical results. Here, a constant cost-per-QALY value must be used (Johannesson, 1995).
But this is problematic because the use of one societal WTP-per-QALY figure means that
differences in individual valuations of a QALY have to be ignored. Simply overriding
individual preferences will do this, but this does not sit easily with the welfarist tradition.
Alternatively, conditions can be imposed on individual preferences and this is the approach
favoured by many economists.