Long interviews could probably be split into multiple stages, but that means more traveling for the candidate and a slower process. There has been a lot of research on this topic and the conclusion is that there is a correlation between how many days the interview process takes with how likely a candidate is to accept an offer, and it’s not a great. Essentially, the longer the process takes the less likely candidates are to accept the offer. Usually when I run interviews we try to keep the time commitment to under 4 hours. This process is draining for both sides of the table, so it’s in everyones best interest to keep the interviews as short as possible. The point you raised about knowing what a candidate is interviewing for and what skills the company is hoping they will add to the team can really help speed up the process. Unfortunately not all interviewers understands the importance of showing up prepared. After all, an interview is a 2 way interaction. We need to impress you so that you want to join our team as much as you are impressing us so that we want you to join. When interviewers actually understand this fact, the the process generally becomes more cooperative and informal(hopefully without the lack of professionalism).
