It's harder to gauge someone's ability when they come from outside the institution initially. Plus, since org Chem is not a freshman class typically, you give s

It's harder to gauge someone's ability when they come from outside the institution initially. Plus, since org Chem is not a freshman class typically, you give students some time to immerse themselves in the culture and standards of the school, and then give them a chance to prove themselves. My undergrad math program was the same - there was a difficult abstract linear algebra class that was the gate to being a pure math major.