The Interview Brainteaser and its Discontents - 7

So are interview brainteasers ever a good idea?

Should an interviewer ever pose a brainteaser for a candidate? It will probably surprise you at this point that my answer is Yes. I see two valid uses for these questions:

• I sometimes use a brainteaser when I am interviewing someone who is relatively inexperienced and there isn't much material for me to work from on his or her resume. I'm hoping the candidate's sharpness may shine more on this less subject-matter-specific problem. When I do this, I'm definitely trying to filter in a candidate who might otherwise be overlooked, not to filter out.
• With enormous caution, having already set a good rapport and carefully set a context, I might try to use a problem like this to see how someone thinks, but I would be acutely aware that I might be posing a problem for someone with more actual insight into it than myself. If they head off in a different direction than I think is correct, I will let them run with it (although after a bit I might ask why they are headed that way and what they are after). I might learn something. At the very least, I will learn more about how the person thinks than I would by guiding him/her to the correct answer as I see it.

Actually, when interviewing an experienced candidate, I almost never use a brainteaser as such; more commonly I pose a hypothetical situation such as trying to clarify a vague requirement brought by a client. I try to frame this as job-situation role-play, and to preface it with something like, OK, a client/ product manager has come to you and asked for this and you are trying to work out the details. Keep in mind that they may not really have a clear idea of what they really need and they may actually be asking for something that desn't make sense. Then I try to give an initial statement of a requirement that is not insane, but also not entirely well thought through, pretty much what I typically see from a marketing department or a client. When I can, I try to draw the example from an area in which the candidate claims expertise.

Along similar lines, if I pose a brainteaser in an interview, I first say something like, This next part of the interview is meant to try to learn something about how you think. Feel free to press me for any information you think would be useful to solve the problem, and I'll do my best to give it. I also say explicitly to the candidate that, as always when someone comes to you with a problem, I may not fully understand all the ramifications myself, so you should feel free to question my premises.

Also, if the candidate can't solve the problem, I would always tell him or her my proposed solution. Maybe my solution doesn't really work. Maybe the candidate has already thought of it and rejected it for a good reason. Maybe I'll find something out about the candidate if I give him/her a chance to poke holes in my thinking about the problem.

I am aware that some interviewers will pose a truly unsolvable problem if they believe that the key to a particular job is the ability to handle enormous stress. There is almost no chance that a person in a job interview will work out firmly and confidently in a matter of minutes that the problem is unsolvable, so all the interviewer will typically get to observe in this scenario is the candidate's behavior under exacerbated stress. (I have never actually used this technique myself, and I don't believe I would be comfortable doing so. Still, I would venture to suggest that if you are going to deliberately ratchet up stress in an interview, this should be done by a professional from a Human Resources department, not by the supervisor-to-be. The supervisor should get to play it straight and establish a rapport with their potential new subordinate. The stress interviewer had also better know in advance what he or she plans to say if the candidate calls the bluff and asks point blank, Do you believe your problem has a solution?)

In any case, a brainteaser well-used in an interview is, precisely, a tool to learn something about how someone thinks. It's not simply a tool to see how clever they are. Frankly, computer professionals are usually pretty good at gauging how clever someone is, and we don't typically need to pose brainteasers to do it. Conversely, few of us are experts at learning how someone else thinks, and throwing brainteasers at them is not, in and of itself, sufficient to learn that. Learning something relevant about a job candidate from watching him or her try to solve a brainteaser requires something that goes totally against our usual bias as technical professionals: it requires letting go of whether the person is headed toward what we believe to be the right answer and instead observing whether they are headed along a process that will often be useful in our organization.This is particularly tricky, because often the most useful person for us to find would be one whose intellectual processes do not simply duplicate our own, so our insight into those processes will probably be limited.

Dealing with this as a job candidate

Ha! So you think you can deal with this as a job candidate?

Sorry, I couldn't resist. I make no secret of the fact that I find brainteasers very hard to deal with as a job candidate in an interview, so maybe this is the blind leading the blind.

Of course, next time this arises, I now can say, Funny you should ask me that, I wrote an article you might want to read.