The principal rationale for prioritising help to the world's poorest is how little money it could take to improve their welfare.
In childhood, we are told stories of how rich people are bad and poor people are good. It is something of a problem, given that, globally, we are the richest generation in human history: Mediaeval royalty had poor healthcare and life expectancy - and no Internet. However, we can take some comfort from the fact that, by its end, we can expect to have been among the poorest generations of the still new millennium. Even Bill Gates will have many deprivations compared to some future generations.
On the other hand, as we grow up and put away childish things, we are increasingly told that the poor are feckless, tax is theft and that the rich work hard for their money - as if the poor do not.
If it sounds like we are being hit by propaganda, that is hardly surprising given how recently the Cold War ended. Of course, the propaganda is also frequently self-serving: few people argue that they should be paid less for what they do. A more reasonable assessment is the one the Irish writer and critic Mary Colum expressed to Ernest Hemingway: "the only difference between the rich and other people is that the rich have more money." In the same way, the powerful are like the weak just with more power.
Who is rich and who is poor? Apparently most millionaires do not see themselves as rich. Compared with the bottom billion, however, the world's top 3 billion are very wealthy, to say nothing of the top 1 billion. However, many of that top 1 billion are currently unemployed, depressed or facing serious health difficulties. Many of the bottom 1 billion are fairly happy. Both groups contain what would commonly be regarded as nice people and nasty people. Both groups contain men, women and children who are suffering and who could be helped.
Many of the biggest global health problems are common to every country: heart disease, cancer, depression, obesity, smoking, road accidents. These problems often relatively neglected in lower-income countries despite their increasing life expectancies and growing problems with tobacco marketing and obesity, for example.
Nevertheless, rich and poor countries and populations do not experience the same burdens of disease and disability. When it comes to children, the differences are stark. Millions of children under five die every year from poverty. Every 20 seconds a child dies from diarrhoea. UNICEF estimates that 165 million children are stunted due to malnutrition. Citizens of the rich world enjoy democracy, human rights, public services, safety nets and peace in far greater measure than the bottom billion.
The most important difference between rich and poor may be how little it can cost to improve the welfare of the world's poorest. Vaccination, improved sanitation and cheap treatments for malnutrition and diarrhoea, for example, can save lives at very little expense. Tackling unemployment in wealthier countries and some preventative health measures may potentially pay for themselves but, in general, it takes much larger sums to produce the same impact even on poor people in wealthier countries. (Of course, not all problems are caused or solved by money.)
A group of the world's leading economists have said that top priority should be given to bundled interventions (including micronutrient provision, and also complementary foods, treatments for worms and diarrheal diseases, and behavior change programs) to reduce undernutrition in pre-schoolers. According to their report, "For about $100 per child, this bundle could reduce chronic under-nutrition by 36 percent in developing countries. The expert panel noted that the educational benefits as well as the health benefits should be taken into consideration. Even in very poor countries and using very conservative assumptions, each dollar spent reducing chronic undernutrition has at least a $30 payoff”.
By spending $3 billion, more than 100 million children could avoid stunting and malnourishment, they found. Other top-ranked solutions include expanding malaria treatment (generating $35 in benefits for every dollar spent), child immunisations, and deworming.
Aoife Ruth of Concern writes for worldandmedia.com of how Nairobi slum communities are tackling their problems with grace, energy and determination and, in the process, providing a massive return on the little assistance they receive. She argues that donor countries could take inspiration from poor communities in Kenya, rather than cutting aid in order to focus on domestic problems.
In recent years, increasing attention has rightly been paid to aid effectiveness and value for money. However, when it is used wisely, one would struggle to get a better return on investment than spending it on the world's poorest.