Another reason not to aggregate elementary and post-elementary school data

This is from a National Center for Education Statistics summary of TIMSS data from the Nineties* when the reform movement was pretty much settling into its present form. They were already sounding the alarm about math and science scores and proposing extensive reforms for grades K through 12, despite the fact that the performance issues were almost entirely limited to junior high and high school.

In mathematics, fourth-grade students in 7 countries outperform our fourth graders (Singapore, Korea, Japan, Hong Kong, the Netherlands, the Czech Republic, and Austria). Students in 6 countries are not significantly different from ours (Slovenia, Ireland, Hungary, Australia, Canada, and Israel). U.S. fourth graders outperform their counterparts in 12 nations (Latvia, Scotland, England, Cyprus, Norway, New Zealand, Greece, Thailand, Portugal, Iceland, Islamic Republic of Iran, and Kuwait).

In science, students in only one country--Korea--outperform U.S. fourth graders. Students in 5 countries are not significantly different than ours (Japan, Austria, Australia, the Netherlands, and the Czech Republic), and U.S. fourth graders outperform their counterparts in 19 nations (England, Canada, Singapore, Slovenia, Ireland, Scotland, Hong Kong, Hungary, New Zealand, Norway, Latvia, Israel, Iceland, Greece, Portugal, Cyprus, Thailand, Islamic Republic of Iran, and Kuwait).

*I'll try to dig up some more recent results just to see how things are trending.

If all students were 15 years old...

Joseph has an interesting link to a comparison of test scores of fifteen-year-olds in different countries. I recommend you go by and take a look. It has some interesting stuff, but what caught my eye was what wasn't there. I couldn't find a complementary break-down for any other age group.

After bad metrics, I think the worst problem in educational research may be the inappropriate aggregation of primary and secondary education. If there was ever a case where two populations should be treated separately it's here. The two systems face different problems of different severity that respond to different solutions.

I'll try to follow up with some specifics later, but in the meantime, when you hear someone making a blanket proclamation about our schools, remember that about the only meaningful statement you can make that's true about primary and secondary schools is that the teachers in both are about to get screwed.