When reformers talk about teachers having the biggest impact on student learning, they are right, and misleading.
Every study ever done to discover the correlates of student success point to out of school factors and the fact that they precede and complicate in school factors like teachers, curricular materials, physical plant and district leadership.
We need to be clear what we are talking about when we discuss school reform. I propose a couple things:
1) Be precise about in-school or out-of-school factors when you talk about what influences a child's ability to get a good education and what we can do differently to influence each of the 2 domains.
2) Be precise about the age of kids you are talking about. Are you talking about pre-school, elementary school, middle school, high school, etc....? It makes a big difference in terms of discussions around discipline, methods/pedagogy, classroom management, and class size, among others.
The reformers (Duncan, Obama, Gates, Broad) never talk about the out of school factors in any meaningful way I think because they know that would mean Progressive policies, and Progressive policies don't make you rich. Obama made that clear when he chose not to fight for a public option during the health care debate. He has also made it clear by hiring Arne Duncan, who screwed up Chicago's schools and has instituted a system of winners and losers (RTTT) for much needed federal education money.
The schools that are suffering the most, and have always suffered the most, are the inner-city, Title I schools because they serve impoverished populations. These populations live in more dangerous neighborhoods, they are often uninsured and therefore don't seek out or get proper medical care, grocery stores are hard to come by in the 'hood, often these households are headed by a single mother who may work 2 or 3 jobs just to get by, and so-on.
Poverty keeps you down. Education can lift you up. In America, we provide a free education for all our citizens, and even our non-citizens. We now need to provide some basic necessities that almost every other developed nation in the world provides, like 1) universal health care, 2) free high-quality early childhood education, and 3) a more progressive tax code.
Providing these 3 things would do more than all the high-stakes testing in the universe to raise the level of achievement of American students.
Just my 2 cents.