Five years ago, Bill Gates made an extraordinary offer: he invited the world’s scientists to submit ideas for tackling the biggest problems in global health, including the lack of vaccines for AIDS and malaria, the fact that most vaccines must be kept refrigerated and be delivered by needles, the fact that many tropical crops like cassavas and bananas had little nutrition, and so on.

No idea was too radical, he said, and what he called the Grand Challenges in Global Health would pursue paths that the National Institutes of Health and other grant makers could not.

About 1,600 proposals came in, and the top 43 were so promising that the Bill & Melinda Gates Foundation made $450 million in five-year grants — more than double what he originally planned to give.

Now the five years are up, and the foundation recently brought all the scientists to Seattle to assess the results and decide who will get further funding.

In an interview, Mr. Gates sounded somewhat chastened, saying several times, “We were naïve when we began…”

He underestimated, he said, how long it takes to get a new product from the lab to clinical trials to low-cost manufacturing to acceptance in third-world countries…

That little won’t buy a breakthrough, but it lets scientists “moonlight” by adding new goals to their existing grants, which saves the foundation a lot of winnowing. “And,” he added, “a scientist in a developing country can do a lot with $100,000.”

Over all, he said: “On drawing attention to ways that lives might be saved through scientific advances, I’d give us an A.

“But I thought some would be saving lives by now, and it’ll be more like in 10 years from now.”

RTFA. A case study – series of studies – in developing philanthropy. Above all else, give the Gates’ credit for their commitment and dedication. It ain’t even easy to try to give money away to help people.