I wrote: (the language of schooling in Singapore has long been English, but the home languages of most Singaporeans are south Chinese languages like my wife's native Hokkien or Malay or Indian languages like Tamil)

And then you replied: it's hard to know what to infer when comparing a giant, multicultural country with a small, much more homogeneous one such as Singapore.

I especially noted the language diversity of Singapore to respond to something I have read over and over and over throughout the years when Singapore is mentioned in discussions of educational comparisons, namely the false idea that Singapore is "homogeneous" in any meaningful sense for the provision of primary education. It is not. Singapore is, as far as I know, the only country in the world with four different official languages (Modern Standard Chinese, Bahasa Malay, Tamil, and English) from different language families (Sino-Tibetan, Austronesian, Dravidian, and Indo-European) and surely one of the very few countries during my lifetime in which the typical person grew up in a home in which NONE of the official languages were spoken at home. Since before independence, the primary language of school instruction in Singapore has been the official language, English, that was at the beginning LEAST likely to be spoken by any school pupil at home. School officials in the United States whine about a minority of pupils who speak Spanish at home, even though they surely also speak English in the broader community (as my neighbors from Spanish-speaking households do). Try to imagine the United States and its level of educational achievement if most school pupils had first of all, when entering school, to learn a new language that they don't speak at home to their parents and rarely speak to classmates when outside of school. That is the amazing achievement of Singapore. (Something similar and only a bit less amazing happened in Taiwan over a just slightly longer time span, when a majority population that spoke Taiwanese or Hakka watched a younger generation grow up as Mandarin-speakers.)

That's not to say that I think the US school system does not have huge room for improvement. That's clear, and I'm hopeful that continued technological development and research will provide amazing breakthroughs. Moreover, we're not even using some of the best methods that are already available

We largely agree on these statements of yours. On my part, I think "research" (on educational methods that already work in other places) are like to have more impact on primary education than "technological development," but I'll take improvements however they come.

I see I omitted to mention in my first post here, an omission I will now correct, a link to a study of PISA results

http://www.hks.harvard.edu/pepg/PDF/Papers/PEPG10-19_Hanushe...

showing that advantaged pupils with highly educated parents in the United States fare particularly poorly in comparison with pupils enjoying similar advantages in other countries. What's really shocking about international educational comparisons is how badly the top-end students in the United States do, as was also shown in the data graphs linked to in my first post,

http://pirls.bc.edu/timss2007/PDF/T07_M_IR_Chapter1.pdf

which provide an excellent example of correct use of what are sometimes called "box and whisker" plots.