It's also true that (IMO) we're trying to get everyone to meet a benchmark that a fair number of those people probably CANNOT meet. The reasons are myriad, of course-- but some of those problems are mutable and some of them aren't. Until we start (as a society) teasing apart which problems can be fixed in that cohort, it seems an awful lot like throwing good money after bad.
Well, we actually need to start before K. This is why Obama is pushing pre-K, to the dismay of the right and the left and so on and so forth. The research is fairly strong, but it has to be really, really good pre-K, not cookie-cutter, with trained teachers teaching a complex curriculum with care, sensitivity, and community support, and unfortunately that probably doesn't scale at all well.
Here is a less optimistic take on pre-K from someone who has studied it a lot:
http://www.brookings.edu/blogs/brown-center-chalkboard/posts/2014/02/26-does-prek-work-whitehurstDoes Pre-k Work? It Depends How Picky You Are
by Grover J. "Russ" Whitehurst
Brookings
February 26, 2014
...
Not one of the studies that has suggested long-term positive impacts of center-based early childhood programs has been based on a well-implemented and appropriately analyzed randomized trial, and nearly all have serious limitations in external validity. In contrast, the only two studies in the list with both high internal and external validity (Head Start Impact and Tennessee) find null or negative impacts, and all of the studies that point to very small, null, or negative effects have high external validity. In general, a finding of meaningful long-term outcomes of an early childhood intervention is more likely when the program is old, or small, or a multi-year intervention, and evaluated with something other than a well-implemented RCT. In contrast, as the program being evaluated becomes closer to universal pre-k for four-year-olds and the evaluation design is an RCT, the outcomes beyond the pre-k year diminish to nothing.
I conclude that the best available evidence raises serious doubts that a large public investment in the expansion of pre-k for four-year-olds will have the long-term effects that advocates tout.
