3 to 1

GROVER J. “RUSS” WHITEHURST: One of the points, Jane, that's made is that if we had linked data systems, we would be able to have a fair accounting of what works and what doesn't. My bias is it's a lot harder than just having the data systems. But you’re an expert on this.

JANE HANNAWAY: [W]e were focusing on in particular was value-added measures of teachers. Teachers, I think, are arguably, and there is evidence to show the most important in-school factor affecting student achievement, number one.

Number two, there’s huge variability across teachers and how productive they are, a three to one ratio in terms of teachers who are at the low end of the distribution and teachers at the high-end of the distribution.

[snip]

Determining which of those teachers are indeed the most productive ones is a difficult technical task that we're working on. I think the bottom line, where we are right now, is that we can estimate these differences fairly well, not perfectly.

FACING THE FUTURE: FINANCING PUBLIC SCHOOLS
Monday, December 1, 2008