Six problems with comparing student performance across boarders…

1.) ethnic heterogeneity (many of “best” systems in world are ethnically homogenous)
2.) US emphasis on “well roundedness”  (eg. sports and other extra curricular activities).
4.) US does less tracking than many other systems.
5.) All other systems are national rather than local.
6.) In top performing school systems, teachers come from the top 10% of their classes
not the bottom 30% as in the US.
What do you think about comparing student performance?