Monetary losses on a global scale

I am subscribed to the NEPAD newsletter. The New Partnership for African Development.

In it they say:

So I am wondering how this loss of “Billions per year” is calculated. Is this referring to the money spent on aid that is not recouped by the NGOs, Governments and Corporations that put money in? Is it calculated based upon revenue that could have been earned if those people not starving to death were capable of being good little workers? How exactly are they valuing the death of these people?