Interviewed 8 individuals in one day. 9AM - First round of interviews consisted of half of the group going for a typical 1:1 interview, while the other half went to the case study interview. 1PM - Two individuals were chosen from the first round. Second round consisted of a 1 hour case study interview in front of 2 individuals. Case was read aloud by one interviewer, you are expected to take notes, then both interviewers ask a series of questions to get a feel of your thinking process. Advice: Talk through your thoughts in the case study. They aren't looking for the right answer, but rather, how you think and how you answer their questions. Be confident, but methodological. I looked at the online interview practice from McKinsey's website. It is more quantitative than this interview, but helped me to prepare. The people come off as very nice and open, however, you have to be very careful of everything you say and do because you are judged 100% of the time you are around them - even the office people. It is a cut-throat environment, so buckle your seat belt.