And yes, the answer is a little deeper knowledge of school reform is helpful, so you can skip the rest if you want...
The reason I keep coming back to Paul Tough is that I think he's doing good reporting about current school reform initiatives, but his analysis is thin. His post today on the difficulties the first classes to move from Achievement First middle schools are having in the new Achievement First high school is interesting. It also is a demonstration of why he has too much faith in the power of the "conveyor belt" strategy, that is, the idea that if we can just get kids in a coordinated sequence of high-quality schooling from early childhood on, we can close the achievement gap.
Now, obviously, this is a desirable goal in itself. Nobody is going to argue for, say, low-quality middle school. But the question is, in effect, whether the effects are additive or multiplicative.
The thing is, if you're curious about the effects of K-8 or K-12 "conveyor belts," there are plenty of existing examples. Off the top of my head, here in Providence we have Times2 Academy, a K-12 charter, a couple blocks from my house we've got CVS Highlander, a K-8 charter designed in part to feed into The Met high schools, which are run by the state. We've got Paul Cuffee School, a K-8 charter expanding into high school. A couple years ago we came within a hair's breadth of setting up a formal feeder relationship in the between (what would have become) the neighborhood K-8 site-based elementary school and the neighborhood site-based high school.
The whole idea is pretty common. One of our last superintendent's big ideas (which didn't happen) was to convert the whole district to K-8. Most of the private schools in town are K-12.
Good schools at all levels, with good coordination and communication between them, is a good idea, but if it was the idea, we'd know it already. What happens if you start the process with prenatal care is another, more interesting and less explored question.