Dear fellow interviewees,
I had 1st round interviews for an entry level position (Associate Consultant) with BCG a couple of months ago: 1 online case and 2 interviews. Both of my interviews were with partners.
The cases were alright, not too hard to structure and begin with. However, one of the partners didn't give me any time to briefly structure market sizing later in the case and my final recommendation. "just do it on the spot" - I definitely wasn't prepared for that and it took me by surprise.
Another time a director/principal played 'dumb' during the whole interview. I only know that he was playing this role, because he called me later to give me feedback and then talked completely normal with me.
Just a little heads up. It might help if you think constructively of all kinds of interview scenarios and how to best act normal, and of course practice structuring without taking time etc.
Good luck!