Originally Posted by SiaSL
Originally Posted by indigo
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?
Not readily available, hence it is prefaced with "I believe..." as opposed to, "According to XYZ and ABC...".

Originally Posted by SiaSL
In the specific context of high school rankings?
This was actually presented in the context of "this Rube-Goldberg-esque educational machine", not specifically in the context of high school rankings. Several entities are present including news media, high schools, CB (implied as it is the subject of the thread), and the overall industry.

Originally Posted by SiaSL
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).
I am unsure where you are going with this, and not following your train of thought...?

However the FAFSA asks about this in questions 14 & 15 (citizen status / alien registration number) (link- http://studentaid.ed.gov/sites/default/files/2013-14-completing-fafsa.pdf)

Additionally, districts may keep a folder and/or electronic record for each pupil, including demographic characteristics. Once information is obtained a body of historical data may exist even if new data is no longer collected.

Originally Posted by SiaSL
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.
You may have answered your own question: Much data may be obtained by self-reporting.

In addition to schools/districts asking about this, the FAFSA also asks about this (see link above). The American Community Survey (ACS) of the Census Bureau does as well. The ACS materials state that they verify various data points with information held by other Agencies.

First generation programs have been mentioned on the websites of several educational organizations including ACT and AVID. Website content may change frequently.

Various college admissions may differ in their practice of whether first generation means parents had high school only, never admitted to college, attended some college but did not receive a degree, attended 2-year rather than 4-year college, attended college in another country therefore unfamiliar with American college matriculation.

Because you may know best what it is that you are looking for, no doubt your own focused research will best answer your questions/concerns.