If colleges are need blind, how do they know to admit students that are low-income?
The secondary school report includes general demographic data of your HS. That’s the first indicator (% kids eligible for free/reduced lunch, % kids to 2 or 4 yr colleges, % kids who graduate in 4 years). You also submit some general data about parents’ professions, if any.
The rest is just college familiarity with various districts and zip codes. If your family has extenuating circumstances (e.g. you live in a high income district but your family faces financial difficulty or has a low income) – have your GC note this in his/her write up.