The importance of raising teacher quality and a ramped-up declaration of support for charter schools are the education points getting attention from Bill Gates’ first annual letter about the state of his philanthropic giving. But here’s another really important point that Gates makes about his efforts to improve American education:

Unlike scientists developing a vaccine, it is hard to test with scientific certainty what works in schools. If one school’s students do better than another school’s, how do you determine the exact cause? But the difficulty of the problem does not make it any less important to solve. (Emphasis mine.)

A hint at how the foundation might improve educational research is in my feature on the Gates Foundation’s new direction from late last year:

One initiative will invest about $7 million in a partnership between three research groups, the Educational Testing Service, the Rand Corporation, and a University of Michigan research group, which will study ways to measure teacher effectiveness. The goal is to find “fairer, more powerful, and more reliable measures” than current standardized tests provide, the foundation’s director of education programs, Vicki Phillips, said.