As others have described, upon receiving an interview you are instructed to take three online tests. The recruiter sent me several emails with sample tests and links to online practice tests. While these tests were not identical to the test that I took, they were very instructive. Overall, the tests were not hard, but you should take them seriously because I've heard of folks blowing them off and getting dinged for the interview round despite having great resumes. After these tests, I was brought into the McLean offices for a full day of interviews. I met 7 people, and the interviews fell into three buckets: fit, behavioral, and case. I had 2 behavioral interviews, 2 case interviews, and 3 fit interviews on that day. One of the fit interviews was a 2-on-1 over lunch. The rest of the interviews were 1-on-1 interviews. They are very focused on process and human resources. I was later brought back for another day of interviews with 2 people (1 fit, 1 case).