About half of all Africans subsist on $1.25 a day or less, while the average American’s daily consumption requires $131.50. Life expectancy in Africa is 51 years, a full 33 years less than in the East Asian gambling haven of Macao. Per capita incomes have declined or stagnated since 1973. One economist suggests that life satisfaction is so low that the average Togolese man would be hospitalized for depression if he lived in Denmark.

The crusade to “save Africa” has a long and disappointing history, writes William Easterly, an economist at New York University. Between 1960 and 2006, the developed world contributed $714 billion in aid, and still the majority of the “bottom billion” of the world lives in Africa. With so much spent to so little effect, it is particularly important to study what has worked, and why.

The two most heavily trodden paths toward saving Africa are the “transformational” and the “marginal.” Transformers want to make comprehensive changes to advance economic growth or improve social conditions. Marginalists believe in one-step-at-a-time efforts such as administering deworming drugs to schoolchildren or offering merit scholarships to high school girls in Kenya. The ambition and costs of a transformational plan would seem to require a strong base in research, Easterly says, but existing studies are woefully inadequate. It is almost always impossible to figure out what goes awry in transformational projects, in part because so many policy interventions take place at the same time that none can be surely identified as the culprit.

Development ideas cycle through Africa with the regularity of the ocean currents of El Niño. Britain’s Lord William Malcolm Hailey issued a report in 1938 making the case for malaria control, better nutrition, improved soil fertility and erosion control, better land tenure rights, and clean drinking water. Each objective was repeated in the United Nations Millennium Project of 2005. In fact, Easterly says, as each transformational effort seemed to flop, the response was to launch an even more ambitious undertaking, or to try the same thing again once enough time had elapsed to forget the lack of results.

Over time, development specialists have blamed Africa’s poverty on a lack of saving and investment, poor infrastructure, weak agricultural technology, poor education, bad policies, corrupt institutions, violent conflict, military coups, natural resource dependence, failed states, and even  a uniquely bad disease environment. So far, no comprehensive remedy has been found. But research on small, marginal development projects has also been flawed. It has led to overpromising and dogmatism from proponents, and “heroic extrapolation” from small samples to general conclusions, Easterly says.

Yet African development is not a hopeless cause, he believes. It may be that the potential of outside Good Samaritan nations and agencies to “save Africa” has been trumpeted too much. Perhaps those most likely to save the continent may be the Africans themselves.