As an off-campus hire, the interview process was much faster. There were 2 phone pre-screening interviews, basically to evaluate your interest in consulting, and then a "power day" with 1st round interviews in the morning, and 2nd round in the afternoon (if you make it to the 2nd round). The interviews were a typical mix of case/fit. Interviewers were at the level of a manager and above, expect to meet at least 1 partner in the second round. Although ATK typically includes a presentation portion in the interview process, I did not get one.