- A senior team member.
- The most junior team member.
The senior team member is expected. This is the guy who's going to see how good the candidate really is. Depending on the position, this can be a very technical code-oriented interview. Alternatively, it can be a very test design and testing-oriented interview.
I find I learn some really interesting things putting a junior team member into an interview. It's unexpected, and anything that gets a candidate away from the expected questions and answers is a good thing.
There are a few candidate reactions to my junior team member:
The candidate starts talking down to the interviewer, usually trying to show he can be a mentor. Sometimes it's just nervousness, but sometimes it's a real personality conflict.
This is the special provenance of the insecure candidate. With this candidate, you'll find that the more senior interviewer had a hard time getting concrete information out of the candidate and walked away with the impression that maybe he doesn't know as much as he thinks he knows. The more junior candidate walks away shaking his head over the plethora of terms that he didn't think went together quite that way.
When the right candidate walks out of an interview with the junior team member, they've both learned something. This is a candidate we're almost certainly going to move forward with.
So learn what your candidates know, and watch how they react ... to the people with more experience and to the people with less experience.