Over the weekend I came across this blog entry.
I do a lot of interviewing and I am very aware of how difficult it is to make an interview effective so I am always interested to read about interview techniques for software engineers.
Mostly, these focus on problem solving but I distrust these. I do have a collection of interview problems, some based firmly in software engineering and others more abstract, but I have tried them all myself and I don't believe that the ability to solve arbitrary problems under interview conditions is a good indicator of ability.
To be more accurate, I don't believe that the inability to solve one particular problem under interview conditions shows that an engineer is incompetent in general.