I applied online. The process took 1 week. I interviewed at Cornerstone Research in Feb 2011
Interview
I applied online and through my university's recruiting system with my resume, cover letter, and transcript. I had an on-campus interview with two back-to-back 30-minute case interviews. The interviewer will spend about 5-10 minutes asking you about your resume, and then dive into the case. Frameworks don't really apply to these cases, because the interviewer will ask you the questions they want you to answer. I got asked to calculate damages for two potential lawsuits. Second round interviews are the same format, but with 6 back-to-back case interviews - more of an endurance test. Be prepared to be there for 3.5 hours.
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.