Two months ago, Bill Gates told the Wall Street Journal that private money—including upwards of $5 billion in Gates foundation funding—"didn't move the needle much," in terms of substantial, measurable improvements in student achievement and graduation outcomes.

"It's hard to improve public education—that's clear," Gates said. "If you're picking stocks, you wouldn't pick this one."

Today Melinda Gates and Mr. and Mrs. Warren Buffett are talking education reform with NBC's Education Nation. With Gates' WSJ comments in mind, City Limits asked foundations and groups they fund: Do private dollars make a difference in public education?

The answer: Mixed.

We approached top education-reform funders like Gates, Ford, Carnegie and the Broad Foundation. We reached out to New