Which is harder to get into, Purdue or Columbia?

Columbia is much harder to get into overall. It is one of the most selective universities in the country, with an admissions process that is extraordinarily competitive across majors, while Purdue is selective in some programs but not in the same overall tier of admission difficulty. In everyday admissions terms, a student who is competitive for Purdue is not automatically competitive for Columbia, but a student competitive for Columbia would usually be academically strong enough for many Purdue programs.

The main reason people mention Purdue in selective contexts is that certain majors, especially engineering, computer science, and other high-demand STEM fields, can be quite competitive. Purdue is a large public research university, so admission can vary a lot by program, residency, and available space. That means Purdue can feel hard to get into for specific applicants, especially out-of-state students targeting its most sought-after majors.

Columbia is different because the baseline selectivity is extremely high no matter what you want to study. It reviews applicants in a very compressed pool of top students, and strong grades and scores alone do not make someone close to a likely admit. The overall level of competition is simply much steeper.

So if your question is the broad one, which school is harder to get into in general, the answer is Columbia by a wide margin. The only nuance is that Purdue can still be very competitive in particular programs, but that does not make it comparable to Columbia in overall admission difficulty.