The process took 4 weeks. I interviewed at Booz Allen Hamilton in Sep 2009
Interview
My friend referred me directly to the hiring manager and HR contacted me in one week for on-site interview. The on site interview is about 4 hrs long and I would say the interview questions were fair.
Later after i joined the company, I also participated the interview-hire process. Per the process, 3-4 people were required for each candidate and there was a key interviewer assigned. The key interviewer is responsible to write down the review and give the recommendation.
I applied through an employee referral. The process took 1 day. I interviewed at Booz Allen Hamilton in May 2010
Interview
It was a hiring event and Booz brought in about 100-200 people to interview with about 40 staff. Each business unit and government client had a station and you rotated through the stations talking to the Boozers at each table. It was a great interview process.
The process took 2 days. I interviewed at Booz Allen Hamilton in Jun 2011
Interview
It started out with a phone interview. They wanted to verify a few things on my resume and talk about my interests. They then proceeded to the 1:1/Group interviews. The trip was all expenses paid, which was pretty cool considering it was only my second real interview. The interview process took about three hours where I spoke with five different departments. I was a bit nervous when told I would be having four to five interviews in one sitting; however, everyone was approachable and knowledgeable. They simply ask you questions about your interests and experience. You are trained after being hired, so it seems to be kind of a personality interview combined with what you know.