I can't help but think that this is due to a combination of selection bias via the applicant pool and interviewer bias. It's kind of ironic that his logic is f

I can't help but think that this is due to a combination of selection bias via the applicant pool and interviewer bias. It's kind of ironic that his logic is flawed here - "I interviewed 120 master's program applicants and none of them knew about contrapositive equivalence - therefore students are no longer learning basic logic rules in undergrad." I'm making a big assumption here, but the way this reads, the author sounds like the kind of interviewer who would get frustrated if a candidate wouldn't immediately know the answer to a question or if a candidate asked for clarification, and subsequently write off a candidate before the interview's over. If that's the case, it's not entirely surprising that 100% of his interviewees would fail this question.