The classical method of interviewing (either in person or over the phone), I’ve always found to be quite useless. It does have a ‘weeding’ effect of removing the completely clueless, but that’s all. The problem is when you ask people to describe protocols/systems/methods etc you’re testing their booksmart skills, not their real world ones.
I’ve always loved the idea of a practical test, where some kit is set up in a ‘mini lab’ type setup, and a number of trouble tickets are given to the candidate. This will answer the ‘can they troubleshoot’ question! However it’s quite time consuming to set up and grade – if you’ve ever tried to write these kinds of tests they actually take quite a lot of time to get clear and fair.
As an alternative – there is whiteboarding a problem, where the candidate is given a theoretical issue, which they need to talk through their troubleshooting techniques for. It’s simpler to do for the interviewer, but can be quite daunting for people who are not used to public presentations.
In general, making someone answer an open question (e.g. show me on the board how OSPF works) will really test the depth of their knowledge – beyond being able to regurgitate the books they’ve read. However, again you have the problems of nerves and people unused to standing up and presenting. If you’re not looking for ‘public facing’ staff, are you ruling out people based on a skill you don’t need? Speaking to recruiters, this kind of method can rule out a lot of people!
I’m really interested to hear your comments on this one. What have you done (or had done to you!) over the years, and what do you think worked and didn’t work!