Having just come out of high-school recently, I figured it would be helpful to lend my point of view to this debate. I will preface this by saying that conditions are obviously different region to region. I speak only of my region, not for all of them.
I attended a private school, but had a lot of friends in public school (I rowed with them through high-school at a local club). What I can say is that, at least in my neck of the woods, the disparity in education did not come from whether or not you were in public or private school. In all honesty, I think the proportion of straight-A, 1600 (now it's 2400) SAT score kids was about the same. The only thing that I got out of my private school education that the public school kids didn't was better facilities and a few more extracurricular opportunities. I don't think it's as clear cut as "private" vs. "public." I think that, in places like the East Coast (and this may be incorrect, but it is just my experience in dealing with students from those regions) many urban public schools in the spotlight are failing, while the private schools are much more established with a long legacy of wealthy families who have continually upped the prestige of the school itself. The urban public sector lies locked in this downward spiral while the private sector keeps getting reinforced with the "Old World Blood," prices and exclusivity continue to climb, and you get more and more kids thinking that because they are in the public sector in this terrible system, they can't do well. At this point, the education debate becomes more financially driven on the student's side, and not on the educator's side.
(A quick aside - my college rowing coach detested those prep school kids; they were the people who came from St. whatever's boarding school and thought they were the best thing since sliced bread. He would just go on and on about how much he hated "the kids who were born with the silver spoon in their mouths and didn't even recognize it - you know, the Dupont's, the Rockefeller's, all those high up's....")
In other words, it might not be the actual teaching that contributes the most to success post-highschool but rather, the environment in which the kids grow up in, and the subsequent networking they can acquire. There are a great deal of kids at my university who got where they are not because of test scores or intelligence, but simply because they have money and connections. We (my friends and I) went through that whole process during recruiting for rowing at the Ivies. It was very common for us to talk about "such and such a person is dumb as a brick, but they're legacy recruits and their dad knows someone/they're loaded" etc, etc. It came to the point that a lot of us joked that after a certain cutoff, your academic resume was irrellevant and it became a function of what numbers were on your tax returns. Test scores and GPA and all of that were, for the most part, the same between private schools and public schools in my region. That's not to say that the public schools were exceptional or the private schools were terrible, but each produced a number of very intelligent people if you're evaluating them solely by their academic resume.
I think the true disparity between "public" and "private" lies in the ability to cushion those who don't really care about school. In public school, if you don't care about doing well, fine - you aren't really encouraged to pick up your game and struggle through it all, etc, etc. In private school, you get an academic tutor, and they push you along and make you apply to college, you get help from individual teachers, whatever. Personally, I *hate* that. But, let me make a distinction - I hate that it is offered at private schools for kids that don't care, not for kids that need it. I think it is a great thing that it is offered for kids that need it and want to succeed, and that is where I think private schools truly surpass public schools. Private school, for me, was a breeding ground for two, unequally distributed groups of people - those who recognized that school was important and they needed to work and do well (the much, much smaller group), and those who really just didn't care about school and sort of meandered their way through classes because they could *afford* to. They had no concept of what necessity, poverty or more broadly, a state of discomfort, was simply because their parents could afford to pay the bills and they could leech off mommy and daddy. So they did, and they didn't really care about anything because they knew they would be taken care of, whether or not they got A's or D's. A lot of those classmates have since failed out of college or are attending community college, after squandering away tens of thousands of dollars of their parents money in education. It disgusts me, and I won't even talk to those people anymore. It's different, I think, in public school. A lot of those kids have a more realistic idea of what's in store for them if they don't work - whether or not they capitalize on that is a whole different story.
There are definite trade-offs though. One of the glaring issues that I've discussed at length with some of my former classmates is the differences in our abilities to write and do math in college as compared to our current peers. With the exception of the few math whiz's in my high school, the vast majority of us are much more uncomfortable with our math skills when compared to the kids who had public school math. Conversely, I am a far, far better writer than almost anyone I know at college, having tested out of the generally mandatory college writing classes and recieving very high grades in my subsequent rhetoric courses.
Again, this is only speaking for the school districts in my area, but I would hesitate to say that education is poorer simply because it is public, or better because it is private. The issue does not lie as much in the education you recieve as it does in the motivation of the student to do well. That is, of course, influenced by the teachers, but I also think it is influenced by the environment in which the student grows up and their ability or desire to change that environment, coupled with the potential effort required to do so. There is a growing issue with academic complacency and a lack of a desire to learn. I think that is greatly contributed to by a general ignorance of the economic and job-market conditions which are rapidly approaching. The majority of high schoolers and college kids these days don't really understand that the economic world we grew up and lived in, up to a few years ago, is going to turn upside down and you're going to need all the academic preparation you can to stay afloat. They think they can just coast through high-school and college and everything will be ok. We're seeing the first wave of what's on the horizon with the rapid outsourcing of human capital. It's not going to end there.
On a final note, I'll say that while I don't think home schooling is all that great, I don't think it's the education (or lack thereof) that's the most damaging to the individual. Humans are tremendously social creatures, and the prepubescent/adolescent/teenage years are pivotal in human psychological development and capacity to interact socially and integrate. Most of us have no problem with this because we are thrust into interactions of all different sorts in our junior-high/high school years. You severely cripple the social development by cutting yourself off from those interactions. The kids that I have known who have been homeschooled have been of average intelligence, but they are all socially eccentric and awkward. They simply lack the ability to communicate and interact as well as those who have been exposed to a "normal" teenage life.
Whew, that was a lot.
