@ucbalumnus Good question for the author, do they make a good case for it? The empirical data is based upon the tiers as determined below, so it does show a difference in income BASED on the tiers the paper uses.
BTW, I don’t think you should assume anything about a college that is not specifically mentioned.
Here are how the tiers were determined, and it doesn’t include EVERY college, so the assumption that Harvey Mudd belongs in tier 4 is baseless. It could be in tier 1/2/3/4.
“Tier groupings are created in Hersch (2013) and based on a comparison of the 1994 Carnegie
Classification with Barron’s selectivity categories.”