The illegals are primarily from South American countries and speak little to no english.
Not exactly sure why you'd think they'd actually be bringing the already quite low GPA up at all. Care to explain that?
“Care to explain that?”
Surely. We know that Chicago is notorious for youth especially in the gang/murder/shooting department, many of these kids never learn to read, math and so forth and in the end if they stay out of prison they still are unable to attain a decent job because of these limitations. OTOH many of the border stampeders in the big cities (Chicago in this case) are brought in by the parents and are enlisted in public schools. It is these kids who learn English and basic skills because they want to, not because they are littered/tainted by the ghetto life that they are familiar with.
Would think that this sort of situation might raise test scores a bit.