I got the interview through a Career Center listing for the company. They were interviewing a lot of people for the first round: 2 full days of on-campus interviews and 1 full day of in-office interviews. I don't know how they determined who they wanted to invite on-campus or in-office, but I was emailed about a week after the deadline and asked to come to the office. I wasn't reimbursed, but I figured going through the interview and maybe getting a job would be more worth it than deciding not to spend some money on travel. The interview consisted of two 1:1 interviews. Each interview had some resume questions (just making sure you know what you've done and see where your interests really lie), but the biggest portion of each interview was the case. They were portions of actual cases they were working on or had completed. More like management consulting cases than economic consulting. Know what area you're interviewing for and brush up on your economics and business skills. The interviewers were really friendly, and the San Francisco office is really nice. From what I have heard about it, Cornerstone is a really awesome place to work, and the people there are very happy. A week after the interview, I got an email saying that I was not given an offer and that it was a difficult choice for them because of my strong qualifications (typical rejection letter wording). Anyways, it was still a good experience speaking with them and seeing the office. Maybe it'll be a potential place to work in the future(?)