One thing I never see in the income/happiness studies is - Is this just for a single person, or is it for a family? And if for a family, then what size is that family? I can see being happy earning 75k/year and being single, but not so much if I have eight other family members to support with that same salary. Is there some sort of "number of people being supported on this income" adjustment to the income/happiness studies?
At least one study uses household income [1]. The effect isn't adjusted for family size in any way I can see. Do note that the linked study differentiates between 'enjoyment of life' which they estimate starts to plateau around $75k / household and 'life satisfaction' which keeps going up with earnings [2]. That difference may explain much of the supposed controversy as outlined in the original post.
