Few know better than the Gates Foundation how important results are to mobilizing people and money to tackle a problem such as malaria.

But those results are hard to pinpoint accurately, it seems. William Easterly takes a look at some of the recent malaria success claims and finds some of them to be overstated.

KATHY WILLENS/ASSOCIATED PRESS

Bill Gates announced $168 million in funding toward malaria vaccine research at a UN Millennium Development Goals Malaria Summit in September.

Here's what the Gates Foundation said, and we reported, last September:

Several African countries have made progress against the disease using low-tech methods such as bed nets and indoor spraying. In Ethiopia, for example, 70 percent of households in high-risk areas now have at least one insecticide treated bed net and indoor spraying, and effective medicines are available nationwide to treat malaria.

In less than three years, Zambia has seen a 50 percent drop in the number of children infected by malaria parasites and a 29 percent drop in overall child mortality, which experts say is almost certainly due to the wider distribution of insecticide treated bed nets.

Now Easterly cites this more recent WHO malaria report, which takes a step back. The effects of malaria control in Zambia were "less clear," and in Ethiopia, "the expected effects" of malaria control are "not yet visible," he says, quoting the report.

Indeed, other than four countries with small populations -- Eritrea, Rwanda, Sao Tome and Principe, and Zanzibar (in Tanzania) -- in many other cases "the links between interventions and trends remain ambiguous," the report concludes.

In an interview from Davos recently, Bill and Melinda Gates repeated "numbers that have already been discredited," Easterly says.

He traces the claims back to Dr. Arata Kochi, the former WHO malaria chief, reporting 50 to 60 percent reductions in deaths of children in Zambia, Ethiopia, and Rwanda to celebrate the victories of the anti-malaria campaign. Kochi had rushed conclusions from a preliminary report that was never verified, Easterly says.

Easterly admits to his own philosophical differences with Gates, who he says hated his recent book. The NYU economics professor jokes he recovered from the criticism only after "months of intensive psychotherapy."

Easterly has dismissed foreign aid and "creative capitalism" as solutions to help the poor in developing countries, which he says could benefit more from plain old capitalism in the form of foreign investment. One of the other main differences seems to be that Easterly is basically a pessimist and Gates an optimist.

As for evaluating malaria control progress, this could be a key task for the UW's Institute for Health Metrics and Evaluation and its director, Christopher Murray. While financed by the Gates Foundation, the institute has not held off from reporting critical results.