Valerie Strauss:

That’s what Bill Gates said on Sept. 21 (see video below) about the billions of dollars his foundation has plowed into education reform during a nearly hour-long interview he gave at Harvard University. He repeated the “we don’t know if it will work” refrain about his reform efforts a few days later during a panel discussion at the Clinton Global Initiative.
Hmmm. Teachers around the country are saddled every single year with teacher evaluation systems that his foundation has funded, based on no record of success and highly questionable “research.” And now Gates says he won’t know if the reforms he is funding will work for another decade. But teachers can lose their jobs now because of reforms he is funding.
In the past he sounded pretty sure of what he was doing. In this 2011 oped in The Washington Post, he wrote:

Related: Small Learning Communities.