I believe the specific target groups of students are those eligible for free and reduced lunch, ethnic minorities, undocumented immigrants, those whose parents did not attend American college/university.
Do you have a source for that? In the specific context of high school rankings?
NCLB tracks performance for several at risk categories (racial minorities, limited English proficiency, socio-economically disadvantaged, special needs) so that data is readily available.
The federal government defined socio-economically disadvantaged as eligible for free/reduced price lunch, but states seem to be free to extend that (California uses free/reduced price lunch or neither parent graduating high school).
But I doubt anybody is keeping hard data on undocumented immigrants right now, since it is such an extremely sensitive subject (Plyler v. Doe, the recent fight around laws in Alabama and Georgia that required public schools to ask about the immigration status of their students).
And I have no idea where anybody would get the data on whether parents attended an American University. When I signed up my kids for public school parental education levels were self-reported with no box to put in where those degrees came from. Nobody asked me for my transcripts.