I had my first round on campus with only 1 person. I was asked to walk through my resume, how I thought the health care bill will affect employers, why Mercer, why consulting, what I thought consulting was about, team work, biggest challenge etc.
I was notified of my second round much much later, but it was 1 day about 2.5 hours with 6 people, two at a time. I was asked about my biggest challenge, a time that I failed, missed a deadline, examples of teamwork, etc. Really great people!
No cases or problems!