I applied through university. The process took 2 weeks. I interviewed at Harvard University (Cambridge, MA) in Sep 2019
Interview
Walkthrough a mock unit review test. Know how to lead students to answers without giving away the answer (but also while avoiding being overly obtuse). Anticipate potential follow-up questions since the interviewer will pretend to be a student, especially a student that gets answers slightly wrong
Interview questions [1]
Question 1
Q: I don't understand why the price of related goods shifts demand. Can you explain?