It becomes apparent when looking at the lowest and least that the different measures can be usefully compared: in pure gross domestic product we have a list of small island nations with similarly sized populations. Nobody's asking Tuvalu or Kiribati to do the heavy lifting (those figures are billions by the way, I take it Tuvalu doesn't produce anything.)
With the poor list, there is mention of the ebola virus, of revolution and instability in the government and military; the capsule summary is outright declaring their poverty and ongoing difficulties.
From a dry economic perspective, it is of interest to know how the small economies operate. I'm not sure - if you are not working or operating in a country with any of the above - if it is possibly wasteful to factor in the lot of the poorest populace. Water cooler revolution is off the agenda.
Would it be fair to say that there is no correlation between GDP and per capita GDP? Judging by lists both high and low, yes.
There are lists on both ends of the spectrum that different sites place in different order. Nonetheless, I think it is fair to recognise Singapore as a country that has a compact community steeped in commerce and that Japan with all its fingers in so many pies and exceeding the field would be off the scale with raw GDP
I don't think, however much variance* you see, that anyone has managed to confuse Burundi with Brunei in terms of output or wealth to go around.
*yes, I did see Australia appear in one top ten