Fortunately for you, if you don't want to use race to distinguish you can instead use these characteristics to define your subgroups:
1) kids with two married parents at home
2) kids of parents with a college or professional degree
3) kids of parents who work white collar salaried jobs
4) kids of parents who are native English speakers
If you check all those boxes you're going to see that the resulting subgroup does very well on all standardized tests, including PISA. It will also be predominantly white/European-American & Asian/Asian-American. Those four attributes make the biggest difference in educational attainment, and brown & black families are the ones who are being left behind.
For the next thought exercise, consider what can be done to address this shortcoming in our political, social & education systems.
1) kids with two married parents at home
2) kids of parents with a college or professional degree
3) kids of parents who work white collar salaried jobs
4) kids of parents who are native English speakers
If you check all those boxes you're going to see that the resulting subgroup does very well on all standardized tests, including PISA. It will also be predominantly white/European-American & Asian/Asian-American. Those four attributes make the biggest difference in educational attainment, and brown & black families are the ones who are being left behind.
For the next thought exercise, consider what can be done to address this shortcoming in our political, social & education systems.