Once you’ve established that the person has the basic knowledge for the job, you need to figure
out, at least at a high level, how he or she solves problems. At this point I find a whiteboard to be
the best tool for the interview. I always make candidates for programming jobs describe, in block
diagram form, a system they’re familiar with. If a programmer or software engineer cannot describea system as a block diagram, I am pretty unlikely to hire that person. A candidate might be brilliant
and might understand the system he or she worked on, but a candidate who cannot explain it to
another person will be useless in any work group.