I've been looking into how global health programs evaluate the effects of their interventions for a story that will appear in our March issue. Public health experts have told me again and again that too little attention has been paid to evaluation across the board.

This morning (Feb.1), both The Washington Post and The New York Times reported on a study by the World Health Organization that seems to address this issue. The study looked at how well distributing of insecticide-treated bed nets and artemisinin, the newest anti-malarial drug, affected rates of child malaria deaths in Ethiopia, Ghana, Rwanda, and Zambia.

The team found that children's deaths from malaria have dropped by about 50 percent in Ethiopia, where 20 million nets were distributed over two years, and by more than 60 percent in Rwanda, where two million nets were distributed over two months in 2006.

The 33 percent decline in malaria deaths among Zambian children would have been greater if supplies of nets and drugs hadn't run out in many areas, the report suggests.

Data from Ghana, though, seemed a bit more puzzling. Ghana received little funding from the Global Fund, which heavily subsidized programs in the other three countries. This meant that Ghana was not able to buy many bed nets and had to charge patients for drugs. But still, the country saw a 34 percent decrease in child malaria deaths.

The study got its data from local hospitals. It's an improvement over programs that don't do any follow-up monitoring of their programs at all. But I can't help but wonder what additional insights could have been gained from more thorough data collection and analysis. Counting deaths in malaria-stricken children is something, but tracking malaria infection rates in a wider segment of the Ghanaian population might have provided other explanations for the decrease in deaths, such as vector population declines or decreases in transmission rates.

In other malaria news (that happens to intersect my fascination with chimpanzees), clinical trials on a malaria vaccine based on a chimp virus have begun in the UK.