I've been looking at some of the TIMSS stuff for a few days, but dobeln's post prompted me to post.

Here are two trends (source) that I found interesting, re: Race and TIMSS in the USA:

Notice that (1), the White levels have ostensibly leveled off, while

(2) the Black and Hispanic/Latino levels have definitely increased over 3 years, although they might be leveling off (at least in math).*

My initial question was what was causing the differential slopes? And the secondary question was what will the 2007 wave show?

As to the former, I would say that it is the massive funding going into Urban school districts. Where I live, for example, they put oodles of money into a particular school that wasn't faring so well academically and happened to have a large African American population. They overhauled the school's administration, teachers, etc., and I am sure they will find some improvement on achievement indicators. Few would say if you took the best teachers and the best administrators and threw a wad of $ at them that scores couldn't be somewhat increased.

As to the latter, I see all three race groups show heavy plateauing, especially in math, with a Black-White gap of ~ 75, which (gasp!) is about 1 SD.

* I really wanted to see the trend for Asian Americans, too, but the data did not meet some requirement, so the good people at the Federal Gov't decided not to post the data (at least that I could easily find).