I’ve spent a lot of time in HR (stop throwing rocks! ouch! I’m a good guy, really!) and as such have been involved in interviewing, hiring, and supervising various people over the years.
Here’s the thing: You want to find out how somebody will be as an employee, but you can’t ask directly. (For example, “What have you done that pissed off previous co-workers?”) So you have to be somewhat elliptical. But by the same token, you don’t want to try to blatantly trick the person into talking about stuff, because being deceptive is a hallmark of assholeness.
Instead, I prefer an open-ended question that invites people to talk about things, that leaves an open door if they choose to walk through it, that seems to give them permission to show you exactly the sort of stuff you want to know. That’s very difficult, because, in all my years of doing this, I have to say that interviews are generally not very effective in terms of candidate selection. To paraphrase Winston Churchill, interviews are the worst way of hiring people except for all the others.
Anyway, one excellent question I’ve developed goes like this: “Tell me about a project you worked on that didn’t go the way you wanted, and why you think that happened.” (This is similar to the sorts of things delphica is getting at above.)
The keys I look for in the response are as follows:
[ul][li]Blames others, or takes responsibility? Sometimes, things are out of your control. More often, though, it’s easy to push responsibility onto other people. You learn a lot about a person this way; do they go off on a tangent, talking about how some other person was “out to get me”? Do they get angry?[/li][li]What did they learn? If they don’t get into this themselves, then definitely ask it as a followup: “Okay, so, if you had it to do over, what would you have done differently?” Good candidates will have rethought their strategy, and will be able to give details; better candidates will actually have a real-life example of this new approach. Bad candidates will say things like “I’d avoid that jerkoff” or “I wouldn’t do it at all because it sucked.”[/li][li]Do they have more than one example? We all have disappointments in our careers, but if the candidate has a whole string of them, you, as an objective observer, may be able to see that the common thread in all the examples is, in fact, the candidate himself. It’s an especially big red flag if the person says, “Oh, there are so many,” or if at the end of the first example, they say, “Oh, and here’s another one,” followed by a third one. Again, you’re looking for how they learn and grow from mistakes.[/ul][/li]I also make a huge point of leaving about a quarter of the allotted time at the end to ask, “Do you have any questions for me?” Smart candidates will ask about management policies, how the company responds to new ideas and directions, and the like. They may also ask you how you like working there, turning the interview around. A candidate who asks about fast promotions, raises, etc., may be a short-sighted careerist or climber, or they may just be ambitious. I cast a dim eye at candidates who don’t have any questions for me, or whose questions are uninspired or smart-alecky. Basically, when you give this opportunity, the best candidates will have lots of specific questions about the work environment, company (or department) direction, strategy, and the like.
I also think the “what kind of tree are you” questions are a waste of time, but you might be able to use a variation as an interesting icebreaker: “What’s the weirdest or most difficult interview question you’ve gotten?” If you’re lucky, this will actually tell you something useful, if you get someone who dismissively references a past question you actually thought was valuable. If you use the icebreaker question early on, you can also make note of any of your questions that are similar to the one the candidate didn’t appreciate. If you’re really sneaky, you can bring back that very question in a slightly reworded way, just to see how they respond.
Anyway, in general, you want questions that invite specific past examples, rather than loose hypotheticals. The latter are easiest to BS through; the former tend to be connected to actual memories and trigger real emotional and intellectual responses. Hope this helps.