We haven’t seen – either in charities’ grant application materials or in our own independent research – much discussion of how organizations decide where to focus their resources. This question seems particularly important for international aid organizations, which often work in many regions all over the world (but by necessity have to ignore many more).
When thinking about this question myself, one of the criteria that occurs to me is the triage approach: find regions where a little bit of aid goes a long way. For example, let’s say we’re trying to decide where to expand malaria-centered interventions (such as insecticide-treated bednets). Niger, Guinea, Malawi, and Zambia are all countries with relatively high malaria mortality rates (0.17-0.2%, mostly concentrated among young children). However, Malawi and Zambia also have severe problems with HIV/AIDS: approximately 15% of the adult population is HIV positive and 0.6-0.9% of the total population dies from AIDS each year in these countries. By contrast, Niger and Guinea are significantly less affected by this disease (1-1.5% HIV positive, 0.04%-0.1% mortality rate).
From these numbers alone (and of course there is much more to the story), I’d prefer to expand a malaria-focused intervention in Niger or Guinea than in Malawi or Zambia. Our aim is to help people live fully enabled lives; resolving one problem, in an area where that problem is the primary obstacle a person faces (because s/he can now live a fully enabled life), will have a greater impact than resolving one problem where it is one of many a person faces. I’d prefer to protect children who won’t have to grow up with so much to fear from HIV/AIDS, if I have to choose (and I do).
Of course, to really make this sort of analysis work you need to look at a lot more than by-country rates for two diseases; you need to look at smaller regions (which can vary wildly within a country) and get a full sense of the different problems people face, including not only mortality risks but more general health problems (such as malnutrition), access to education and economic opportunity, and political stability. The goal is to find places where a humanitarian intervention can truly make the difference in giving someone a life of opportunity (not just solve one of an overwhelming set of problems).