Skype interview followed by final round super day. The final round was in Arlington with breakfast, then a presentation about the firm, then 4x45 minute interviews with a 90 minute lunch break at some point.

first round consists of 2 case studies, 30mins each. They were dissimilar to a typical business case that you would do for MBB for example. Instead, its much more like a single problem that you have to solve. Will typically be a revenue problem for example or 'should we go ahead with this project'. Behavioural was about 7mins long and is basic. If you clear the first stage, second round is four 45min cases.

I applied through campus recruiting. I had two on-campus first round interviews and then 4-5 second round interviews in the DC office. In addition, the super-day included a presentation, lunch, and a networking dinner the night before. All of the interviews involved a case and some personality questions/questions about why I wanted to join APT. The interview process overall was nice, and everyone I met was genuine and enthusiastic about their jobs. I turned down the offer because the work itself didn't seem terribly exciting.