Some details from the paper:
- The paper studies colleges that offer a three-year undergraduate course in arts and science (no engineering or medicine). So, extrapolating this for IIT/NIT vs non-IITs is just argumentative with no data points.
- The statistical data did not survey students who managed to secure a seat in an elite public college using reservation quota.
- The sample data is from admission cohorts a couple of decades ago (1999 - 2002).
- The detailed in-person survey was done only in urban areas during 2011-2012 time frame.
- Data sample:
* Initial survey request sent - 1981
* Actual surveyed - 1506 (76%)
* Either self-employed or salaried - 748 (49% of surveyed)
* Final data sample - 439 (58% of employed)
# public colleges - 190 observations
# private colleges - 249 observations
- The entire analysis (and the claim) is made comparing the outcomes of students at the margin of admission (around admission cut-offs). So, if a student secured top score and entered into a public college and gets a top dollar salary, the author weakly attributes it to better learning environment.