Global health hit the philanthropic jackpot in recent years. About four times more aid flowed into developing countries in 2007 than in 1990. But a paper published in The Lancet suggests the nearly $22 billion donated in 2007 missed many of the world’s most deserving countries and diseases.

“We know there’s a lot of money,” says Christopher Murray, director of the University of Washington’s Institute for Health Metrics and Evaluation and co-author of the study that tracked both the sources and destinations of aid. “But we also know there’s huge variation in the amount of money per unit of health need.”

Murray lived in Niger as a kid, a country ranked by the World Health Organization (WHO) as the world’s 28th most needy country and home to one of the highest childhood death rates. The development funding for Niger, however, is well below that of wealthier countries like Namibia, which receives “10 to 15 times more aid per year of lost life,” he says. Niger is one of 12 countries on the list of the 30 most burdened by disease that are not also among the 30 receiving the most health aid.

The report also concludes that more than 23 percent of all aid has gone toward HIV/AIDS, while diseases like tuberculosis and malaria—with combined burdens greater than that of HIV/AIDS—receive less than a third of that amount. As Murray explains, the “massive expansion of money for global health” starting in the 1990s had a lot to do with the “reaction of governments and citizens to the HIV epidemic.”

The Seattle-based team analyzed funding from aid agencies in 22 developed countries over the 17-year span, adjusting for the 2007 dollar. The U.S. topped the final list with about half of all governmental and private global health funding. That rank belies the country’s “miserly” reputation in some quarters, Murray says. Though it’s also true that U.S. donations ranked fifth, when calculated as a fraction of national income.

Seattle’s own Bill and Melinda Gates Foundation contributed more than any other private philanthropic organization: 4 percent of all health assistance in 2007. (The foundation also helped fund the study, although Murray notes that the institute operates as an “independent entity.”)

This careful counting of resources—where they came from and where they’re going—could significantly improve the impact of aid, according to the authors. No one had kept thorough tabs before. Private donations, now about a third of all funds, were nearly invisible.

The study “represents a phenomenal amount of legwork,” says Ruth Levine, vice president of the nonprofit Center for Global Development in Washington, D.C. “It reinforces the general pattern that most people in the field are aware of. The major new information is on the private side.”

In addition to private philanthropies, non-governmental organizations and businesses have also increased their influence in global health. “It’s a dramatically more complicated arena today,” Murray says. “There’s a much bigger set of actors with different backgrounds and agendas that are active in global health.”

Many of these key players are in Seattle for meetings this week, including the “Health 8”—a meeting modeled after the G-8, an annual forum of world leaders. Representatives from the WHO, the World Bank, the Global Fund to Fight AIDS, Malaria and Tuberculosis, UNICEF and the Gates Foundation are there.

The aid landscape today is bleaker than in 2007, with funding under pressure amid the global economic downturn. Making better use of the money available is more important than ever. “A pretty large share of the conversation is likely about worries whether and how funding levels can be sustained,” says Levine. “There’s no question that it’s helpful to have this kind of comprehensive information.”