Round 1:
You are required to take a timed (60 minute) test that goes over some basic case studies. You can't use a calculator and many of the questions are heavy with basic math. There's really no way to prepare; you just need to be comfortable looking at graphs/charts and sorting through data tables. You should also brush up on your speed-reading skills, as there is a lot of information given in each question and not much time to answer.
You then participate in two break-out sessions with 4-5 other candidates and a relatively recent McKinsey hire as the mediator. You go over a basic case study, the type of which will be encountered during the Round 2 interview in a one-on-one setting, and the mediator basically asks pointed questions from each person in turn so that everyone has a chance to speak and practice.
Overall, everyone was extremely nice and helpful. The atmosphere in the break-out sessions was relaxed and actually sort of fun. The test was nerve-wracking, but it always comes before the break-out sessions, so you can sort of relax afterwards and do your best to practice your case study skills.
McKinsey told us that whether or not you were called back for Round 2 was based 90% on if you passed the test. There wasn't a score or number of answers specified which designates a pass. I felt that I did pretty mediocre on the test, but I received an e-mail at the end of the next business day inviting me for round 2 interviews. The date and location of the round 2 interviews had already been set when I received the first invitation for round 1, and it was exactly two weeks after round 1.
Round 2:
This interview consisted of two one-on-one case studies with relatively new McKinsey hires. I believe one of my interviewers had been there for 1 1/2 years and the other about 3 years. This was definitely a very difficult and challenging experience, especially because I come from a non-MBA advanced degree.
My first interviewer was a friend of a friend, so things were much more relaxed. They start by telling you the basics of the case, and then attempt to have you come up with a specific solution or "basket" by guiding you through the hour-long process with specific questions. There is always a math question, sometimes two, which requires you to look at a lot of data and logically figure out a way to find the value or amount they're asking about. I had a hard time with this, because again you can't use a calculator and you're nervous, but my interviewer was very helpful in providing tips as I went through the math. Make sure you talk out loud and walk through your analysis instead of just scribbling numbers and blurting out a numeric value. In addition, before the case study started, I was asked two generic questions: "Tell me about a time you were challenged" and "Tell me about a time you showed leadership."
My second interviewer was extremely bored, tired, and in a rush because I was his last candidate of the day. He was less interested in having me give detailed answers because I'm sure he'd already heard it all before. He asked me the same two generic questions before starting the case study, both of which I used different answers than before. The case study went much the same as the first, but I was provided as much help during my math issues.
Afterwards, we were told we could hear back as early as that night or as late as one week away. My interview was on a Tuesday, and I was called by my second interviewer the following Wednesday morning. I expected a lot of feedback, but our conversation lasted all of two minutes. I was told that I hadn't made it to round three; they were just looking for my structure in my thinking process.
Overall, the process is very organized, the people are friendly, and they want you to be as prepared as possible so they give you all the information you need to prepare. Be sure to go through all the interview prep information on the website; this is EXACTLY how my interview went and I was not at all surprised.
