I have a theory, which unfortunately we don’t have the data to prove or disprove: as financial aid has improved at the top schools and their proportions of first-gen students have increased, these schools are admitting more and more kids for whom they’re both the best and most affordable option, and yield ticks up as a result. I think first-gens, unless they’re academically or otherwise elite URMs that many schools want, don’t tend to be cross-admitted much to other top schools with similar financial aid, both because they don’t tend to apply to as many (for example, if they’re matched through QuestBridge) but also because their profiles are relatively more idiosyncratic and may not stand out to more than one of the top schools.