Mercer has a unique interview style and is very concerned about finding a right fit for the company. Overall, it was a very pleasant experience and the people are fantastic.
First round interview, met with an Associate in Health and Benefits and went through introductions. Then I was asked one or two behavioral questions. The interviewer then set everything down and asked if I had any questions about Mercer. They really want to see your interest in the company.
A week later, was invited to Second Rounds at the office. The second rounds consists of 4 back to back 30 minute interviews with Principals and Associates. This is then followed by a lunch with past interns. You may meet up with your original interviewer - which is nice. The interviews themselves were all pretty unstructured and I would suggest that you really prepare a lot of questions to show your interest. I really enjoyed speaking with everyone and it was definitely one of the most enjoyable interviews I've had