I interviewed through on-campus recruiting. My initial interview was just a run through of the resume, very friendly, and very open. We talked a lot about the nature of this particular role-- it is very much interacting with their technology, not thinking about where the technology needs to go. The interviewer was an individual who could have been my supervisor, not a HR person, which was really nice. After a week or two I was invited to a second round interview at their headquarters. This was a great way to really get to see the company and understand it better. I had two, hour long interviews, both with senior members of the PI team. One was behavioral, just a resume overview and making sure we were a match. The second was a case interview--not too math-based, more about the ability to analyze a process. They want friendly people who fit their culture, and their mission. They will be incredibly open about any reservations they have, so be prepared to respond well. I ended up not getting a job with PI, but they connected me with another department to interview with.

It was a standard interview process. The interviewer was really nice. The interview consisted of standard tell me about your self questions. After that there were questions about expereince. Then there were questions about problem solving.