In brief,
In considering per capita incomes, one would have to take into account, amongst others, the 'per capita debt'(debt which is enforced upon all via, amongst others, housing/education costs) and 'per capita liabilities'(amongst others, healthcare costs). Thus, an individual earning 'less' in a semi-socialist state than her/is counterpart in a bourgeoiscratic one may actually be earning more in real terms than the latter.
It is not what one earns but how much of it one gets to keep unconditionally, and how much of what is taken away comes back to oneself that determines the significance of research done on ‘per capita incomes’. Without taking this into consideration, comparisons between countries is nonsense.
Additionally,
'per capita incomes' may have the effect of allowing a significant proportion of the population to think that the stated (local) high 'per capita income' is an amount that may be aspired to as it is already a local reality - albeit applicable to only a small sector of the local population. In other words, since it is supposed to be the 'per capita income' for the particular country, it may be perceived to be an amount that anyone of the local populace might aspire to. This may have the effect of perpetuating the miserable conditions suffered by many amongst the local populace - especially if the 'per capita income' figure is bloated by the amount earned by a small proportion of the population - since little will be done to agitate for the closing of the chasm between the rich and poor.
Of course, to realise this, the respective populations have to be in possession of significant ‘per capita' and 'per individual' intelligence.

The Guilty
Businessweek published a list of what they term, ‘The Top Givers’, which, amongst others, included Bill Gates. What Businessweek forgot to mention is that many of these ‘Givers’ and ‘philanthropists’ also range amongst the ‘Top Expropriators’.
In Truth,
A ‘Top Giver’ is one who ranks amongst the least of the Takers. This is
not to say that the least amongst us ought to give the most from the limited
pool of resources that we are allowed to retain after the expropriators have extracted
their share. Rather, we ought to bring about a system where ‘Top Givers’ are
not undone by their simultaneously and oxymoronically being ‘Top Takers’. Where
the amount expropriated via ‘taking’ exceeds ‘giving’, the latter becomes
nothing but insincere and insufficient restitution.
We ought to aspire towards a society where everyone is a ‘Top Giver’ where
‘taking’ equals ‘giving’. This can only be so where the disparity between
‘taking’ and ‘giving’ is eradicated with extreme prejudice. And this can only
be achieved by the complete and utter eradication of the disparity between
classes via the eradication of class-based systems.
When one thinks about it, for global misery to be attributed to nature, we cannot
have a sector of society taking more than it gives. If this is the case, then
we can never say that we have done everything that is humanly possible to
eradicate misery. It is the humanitarian disbursement of that amount that makes
up the difference between what is taken and what is given that argues for us
having done our best.(i.e. we take a $100 and give $20, we are short of $80 in
our purported attempt to eradicate global suffering.)
For a slideshow of some of those who hold the difference between taking and
giving in their bloated coffers, and who, with the connivance of the political,
economic and psychological infrastructure of the capitalist system, have
perpetuated the conditions that give rise to millions of deaths annually, go here.