I still have a lot to learn in conducting interviews but here’s a few things I learned by interviewing several people a day over a week now.
1. Always give a sample code test first. The test should test how good they are at solving problems, rather than what they know. The test should involve actually writing code. Good questions are open-ended but simple to comprehend problems. I have three questions myself and they all involve solving potentially real-world problems. The first tests their architecture skills. The second tests their ability to follow a specification. The third tests their ability to plan ahead and not make unjustified assumptions. I learned this because I spent a lot of time reviewing candidates, and at the end of the interview I have a so-so idea of how good of a programmer they are. One guy, who claimed to have two years of experience, I was planning on hiring, mostly because he said that and a case he brought up he claimed to have solved at work. Yet when I gave him a sample test, he failed it so badly I could hardly believe he was employed.
2. Ask questions that are open-ended, as opposed to looking for a specific answers. Good questions give the candidate an opportunity to brag about themselves. Every candidate wants to do so, so if a candidate does not brag about themselves this is likely because they have nothing to brag about.
3. Spelling ability is a reflection of intelligence. Not using a spell-checker is a reflection of carelessness, sloppiness, and a lack of pride in one’s work. You can practically hire just based on how good of a speller the candidate is.
4. I’ve never had a case where a candidate gave me a warning sign and then redeemed himsself later. I might end up just following the policy that if a candidate gives me any sign at any time they are not suitable, I will just end the interview.
5. The good people know they are good and tend to ask for more money. The bad people know they are bad and tend to ask for less money. The unscrupulous people will ask for a ridiculous amount of money. However, it’s still worthwhile to bargain hunt. I’ve interviewed people 1/3 the price who are better than their more expensive counterparts.