The process took 2 days. I interviewed at Cornerstone Research (New York, NY) in Feb 2012
Interview
I got the interview through the career center. Consisted of a series of 1:1 interviews.
Everything went pretty smoothly. I knew I was on the right track with the case interviews because the interviewer was giving me positive feedback (e.g. "That's exactly right" or "Good suggestion, that's what we actually did when we were working on this case").
Overall, it was a great experience.
Interview questions [2]
Question 1
What is the difference between a hedge fund and a mutual fund?
I interviewed at Cornerstone Research (Menlo Park, CA)
Interview
The interview was split between behavioral (20 mins) and a economic case. This is the first round, once you do this you will have more case rounds. The superday is 4 back to back cases (40 mins each) in person.
The interview process was succinct, but it was difficult. Depending on the office, they take only a few candidates, so it is extremely competitive, so bring your A-game; you will need to be near-perfect.
I interviewed at Cornerstone Research (Chicago, IL)
Interview
Round 1 consisted of two interviewers. Each one asked a few behavioral questions, followed by a short case. Both interviewers were definitely conversational and easy-going. Each interview is around 30 minutes long.