You've got a mishmash of pretty good and execrably bad in this comment. Context: I'm not a teacher, but my wife is; we've seen what happens when assessment-happy libertarians (or pseudo-libertarians for those who want to get upset with my assessment) actually get to destroy a school system. For the fellow Ontarians in the virtual room, I'm talking about Mike Harris.

For those who want to follow my deconstruction at home, I'm going to refer to the original report[1] and the detailed findings[2] that the original poster pointed to but with live links.

[1] The Economic Impact of the Achievement Gap in America’s Schools Summary of Findings April 2009 http://www.mckinsey.com/app_media/images/page_images/offices...

[2] Detailed findings on the economic impact of the achievement gap in America's schools April 2009 http://www.mckinsey.com/App_Media/Images/Page_Images/Offices....

Let's start with a couple of points that go to history. Fifteen years ago (not too long before I emigrated), Mike Harris was elected in Ontario and started on a massive program of social change from which Ontario has yet to recover. His schools program changes weren't all bad, but could have been achieved much less confrontationally and more smoothly, and could have been done without harming the quality programs that existed before. The basis for all of the changes was rooted in a politicized interpretation of test results that weren't meant for such comparisons by the people who put those tests together (at the time, it was largely TIMSS as the driver).

TIMSS is the "Trends in International Mathematics and Science Study" (http://timss.org/), and at the time, the results were interpreted by the Harris government to show that Canadian students (and most especially Ontario students) were performing badly. One problem: TIMSS was supposed to be a universal student study (that is, all students at the grade level in the school system were supposed to be taking it regardless of ability); some of the investigated countries[3] did selected populations (that is, they excluded their worst students) instead of universal.

[3] My recollection is that the above criticisms were laid against some of the PacRim countries and some of the former Soviet Bloc countries.

Canada, the U.S. and many other countries followed the rules and were subsequently ranked much lower than they would have been ranked otherwise (they still would have been middling-to-low ranking, but not as low as they were). The charges of population homogeneity that you make were also made in Canada at the time ("of course our diverse kids didn't do as well as the uniform kids in Korea").

This last makes one of your conclusions nonsense:

"Then the main reason for the low average US ranking is that the US is a diverse country and the other countries are homogeneous."

Canada isn't homogeneous and ranked 5th in science and 3rd in math on the PISA tests (page 4 of the detailed findings); New Zealand and Australia (both also immigrant countries) exhibited good results. The United Kingdom (a diverse country that has some immigration) exhibited average results. It's also worth noting (page 7) that Canada's performance declined by 5 points between 2003 and 2006; the U.S. declined by 9 points in the same period. (Most countries, in fact, declined, with France dropping by 15 and clustering around the U.K. for overall performance.)

It's also worth noting that the statements on page 8 essentially assume that only the U.S. has changed (e.g., it ignores the efforts that other countries have put into improving and focusses solely on the U.S. lag).

The ethnic make-up of Canada is similar to that of the U.S. as we're both immigrant countries. This isn't about race or diversity. It's about socioeconomic disadvantage (sorry, but it's true). Those two things tend to be highly correlated in the U.S. (and to some degree in Canada, too), but school funding in Canada is much more uniform than it is in the U.S. so that socioeconomic differences are smoothed out but not eliminated. See pages 12-13 of the detailed document.

You choose to focus on the ethnic achievement gaps pointed out by McKinsey, but they don't stop there and go on to point out the income achievement gap. Look at pages 42-45 for how this works. Compare the chart on page 26 (a 3 - 8 times difference in low achievement by race) with that on 43 (a 4 - 6 times difference in low achievement by income). There's strong correlation there.

The entire report is worth reading, not just the bit that you quoted or that I quoted.

You're right, though:

"This time the cause is bad teachers protected by the teachers union. I'm all for busting up the teachers union, but I don't for a nano second believe that bad teachers are really the cause of what is being observed."

The problem is a bad system, not bad teachers (although they exist and should be removed from the system). The problem is local funding that isn't smoothed out so that students with all of the advantages get even more advantages because their schools can afford more and better equipment on the same tax rates. The problem is an over-reliance on quantization of the problem space, when students aren't cogs but are individuals (and if you place performance bonuses, etc. on classroom performance of a test, you get "teaching to the test", not learning). The problem is hunger (hungry children cannot study as well as those who aren't).

There are things to be fixed with how teachers and teachers unions work, certainly, but they should be done with a deeper understanding and NOT by misunderstanding what we do know.

A couple of other points:

"Is there any question how the US Blacks would do against, say, Ghana, Liberia, Nigeria, Kenya, Uganda, Zaire, Zimbabwe?"

One might be surprised. I don't know of any particular test for this, but at least some of the countries you named (and other countries in sub-Saharan Africa) might outperform U.S. blacks; they will, at the very least, be better than your off-hand comment suggests.

"So wonder how US students of Finish descent would do against Finland, Asian descent, against Hong Kong, Canadian descent, against Canada, Japanese descent, against Japan, Australian descent, against Australia? The study didn't say. Ah, wonder why? Why oh why? Maybe they followed the old rule, "If you don't think you will like the answer, then don't ask the question.".

"So the study mostly tried to obscure the obvious cause: For the data they considered, the main cause of good performance is country of origin. Right: In particular, parents are a still more important cause, and it might be possible to dig still deeper."

Um, no. The study does say, after a fashion. Your comment is a little nonsensical, though, because you're simply taking the top countries on the first couple of pages and applying them as ethnicities. As I noted at the top, both Canada and Australia are immigrant countries with broad ethnic diversity (but a strong English/WASP contingent, just like the U.S.).

The rest of your comment is nonsense that's easily covered by the summary McKinsey did and the original data (see page 8 of the detailed report for a sample about post-secondary education). Home schooling is mostly a disaster (home schoolers in the U.S. on average perform worse than public school children on all subjects; this may partially be because most home schoolers in the U.S. are nutty Christians who don't want their children to be able to think critically).

What your prescription for education will do is pretty much put the U.S. results 100% in the toilet, as it ensures that only those people with money will have access to education. Education is not a simple subject, and the libertarian approach will fail--and has already (it's why we have public schooling and that the majority of economic growth has happened since public schooling started).