It was a phone interview, and was conducted by a Senior Consultant. The interview was a little more than 1 hour. Starting with some basic questions, like tell me about yourself, and then move on to technical questions, like ask me to describe the operations research as well as statistical skills that I have learned through my past experience. I have been asked four maths questions. Those questions are not hard at all, except one that might need some time to think over. I was not able to pass to the on-site interview, where I have been told through an hr about one month after the phone interview.