Condition (i) would explicitly remove any factors other than health and consumption,
whilst (ii) requires that any such factors must be related to the identity of the individual. In
different ways, both these assumptions prevent factors such as autonomy and self-respect
from entering meaningfully into an individual’s WTP. In both cases, the per-period utility
function can be isolated downto a positive linear transformation of the functionU(c,N, h) =
c + λh, where λ is the common trade-off between consumption and health and the coefficients
of this transformation may include person-specific factors N (under (ii)).
For Condition 5 to be accommodated within a link between CEA and CBA, we must
relax or replace at least one of Conditions 1–4. However, under EU (Condition 1), both
marginality (Condition 2) and symmetry (Condition 3) are required for utility to be the sum of identical per-period utility functions. Condition 4 guarantees a “nice” WTP function, and requires only that the utility function be (strictly) monotonic and concave in consumption.Using a utility function that is constant or decreasing over some levels of consumption (and which is almost certainly non-concave) will also disqualify almost all standard utility functions and so is difficult to justify.