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The Most Revealing Job Interview Question (refer.ly)
578 points by kevin_morrill on Oct 4, 2012 | hide | past | favorite | 235 comments

Hmm, I'm not sure I like the idea of intentionally trying to steer the candidate off on a tangent. It feels like a trap.

In an interview, the interviewer literally has all the power, and saying "no" or refusing to answer a question posed by the interviewer seems rather difficult.

This would be doubly hard for me since I like to teach (both my parents are teachers and I love to explain things to people so that they can understand them). If a person shows genuine interest in a topic by asking a question that might go in a tangent, I generally want their curiosity to be sated before moving on; in some cases a deeper understanding of a related topic will help educate them on the main topic.

Anyway, I think I would fall for this trap for both reasons (not wanting to refuse the interviewer and also wanting to genuinely teach someone). I'm conflicted.

However, I like the overall idea of the question. So much time during actual real-world development is spent communicating between coworkers about how a system works or will be implemented. I think being able to gauge a candidate's communication/knowledge transfer ability is very important and a good indicator of success.

I'm glad you're conflicted! Because it is a trap, an intentional one meant to simulate the unintentional randomization that happens in real life at work. I'm sure we've all had that thing happen when someone threatens to accidentally scramble your work queue because they don't understand the problem domain as well as you do, so you need to be able to steer and guide the work requests that are coming your way and push back when it doesn't make sense.

My dad's a teacher too and boy does he love to lecture. About anything - digital signal processing, the price of gas, whatever - and that mode of communication is useful in its own context, but not so much when a team of people are trying to get something done together.

If it makes you feel better, I fell for the trap too. I asked Kevin for a demo of the question in action so I could see what it was like to be on the receiving end before I used it on candidates myself. I was the guy he referenced in the blog post that compared poker to backgammon and I was in the middle of explaining how Texas Hold Em taught me essential skills of entrepreneurship when he asked me how many board pieces were in a typical backgammon setup. I lost a good 20-30 seconds there trying to remember, until I laughed out loud and called him out on trying to randomize me :)

I think this would be ok if they said upfront that this is a simulation of a meeting and so to pretend that you are someone attending the meeting, and so explicitly take it out of the context of an interview. When I've been interviewed, we are often friendly toward each other and it's not uncommon for them to just want to chat and go on tangents, especially for throwaway questions that assess fit and culture. And you wouldn't know as the interviewee if this was such a throwaway question.

Basically, no matter what reasons you have for thinking people should do the right thing, you have to keep in mind that their reference set for YOU is all the people who have interviewed them in the past, many of whom were likely dumber and less competent than you. They are going to be acting accordingly.

Really? Because I've said no to folks five layers of management over my head, when I knew their comments to be technically inappropriate. I said it diplomatically, to be sure, but firmly and without hesitation.

I think the question is set up properly for the trap to be fair. Having been given clear responsibility for presenting a topic, a time limit, and the floor, I wouldn't think twice about directing the discussion.

Though I also don't perceive the balance of power in an interview to be that asymmetric, either. Usually they're courting me as much as I'm courting them. If anything, it offers a nice opportunity for a reverse test: management that has a problem with technically appropriate direction is not management I want to work for.

I have mixed feelings about this. I had an interview at Palantir with a self-described "front-end" guy, who asked me to write an algorithm to find a number between zero and infinity, where you could pick a number and you would get a response that would tell you whether or not the number was lower or higher than the secret number. The dude had a particular form of approaching the problem that was not at all the fastest form, in fact, he insisted on starting at zero and using an algorithm that was "2x," which he insisted was "fast enough."

I thought that a system which started at zero and went up by multiples of two was obscenely slow, and I hinted at this, but he insisted on having things his way. In the end I'm sure he wrote me a bad review and I wasn't offered the job (I didn't really want it anyways, given my impression that the team I was interviewing for wasn't that focused).

In any case, I didn't go right now and say this is dumb, but I hinted at a better way, and even this hinting lead to some conflict. In the end I didn't get the job. I'm conflicted if this was the best approach. I could have pretended to be dumber than I actually am and gotten the job offer at least, which at this present moment I could probably use for leverage in the search for contracts or a job, but I couldn't bring myself to accept his not particularly good algorithm (full disclosure: the process was also affected by the fact that my flight was delayed from the east coast, that I got 4 hours of sleep, the fact that I insisted in wearing a tweed coat to the interview, which may have impacted ever important perception of "fit," and that the interview in question was a "surprise" interview after several other interviews).

It's a binary search in infinite space. His solution expands the problem area until the number is in the space and then shrinks the problem area until it finds the number. A better solution is to pick an arbitrarily large number and only expand if you have to--otherwise you're shrinking from the very beginning.

That's how I would have answered the question, anyway. But yes, I've dealt with interviewers like this--typically it's because they don't understand the subject matter well enough to evaluate or accept an answer they didn't prepare for.

I disagree that that solution is unequivocally better. It depends on the distribution of the input data; if the expected value of the number is small, then you're better off starting at zero than dramatically overestimating.

Of course, either way the algorithm runs in O(log n) time.

Within the context of the interview question, the solution is specifically stated to be between 0 and infinity, and you can't surmise that the number is necessarily closer to 0. This is the error that my interviewer made. He was trained to deal with things within the context of situations closer to real life rather than the theoretical box he had established for the interviewing situation.

As for my case, I did attempt to start at an arbitrarily large number (but he wouldn't let me), and then went up exponentially (i.e. x = x * x), bi-secting the space once the upper-bound was found and solving from there.

My interviewer was sadly not that bright and didn't understand my solution, forcing me to re-write it -- incidentally, lecturing me on how wonderful O(log n) is along the way.

> the solution is specifically stated to be between 0 and infinity, and you can't surmise that the number is necessarily closer to 0.

Closer to 0 than what? Infinity? By any reasonable definition, every integer is closer to 0 than infinity.

I think the problem as stated is underspecified; I disagree that increasing "exponentially" (the solution your interviewer described would increase exponentially; your version is doubly exponential, I think) is always faster. Both versions have the same worst-case running time, and if you want to talk about expected running time you need to make assumptions about the data distribution. As a counterexample, if you start with an initial guess of 2 and keep squaring, but the true number is 2^1025, then you end up doing much more work than if you had doubled instead of squaring.

I can certainly agree with you that lecturing in an interview is unproductive. Not only is it understandably off-putting, but it doesn't give the interviewer any additional input to the hiring decision and therefore is a waste of everyone's time. (Unless one of the job requirements is coping well with being lectured to, I guess.)

> By any reasonable definition, every integer is closer to 0 than infinity.

Perhaps, but originally we weren't discussing 0, we are starting with an arbitrarily large number. This problem is exacerbated when you say:

> I disagree that increasing "exponentially"... is always faster ... Both versions have the same worst-case running time

Worst case, sure, but how do you compute average? You could take a selection of n number of integers from 0 to infinity and the number of guesses until you found the correct answer, but of course you can't do this because you can't easily get a random number to test with that is between 0 and infinity. That said, it is fairly clear that x * x is faster than 2x is faster than x+1, but you can only prove this to be true once you pick an arbitrary limit less than infinity -- and the benefits of the better algorithm are only evident as you approach infinity.

Seems like a catch 22. Perhaps there is some expert in set theory as applied within computer science that can provide the appropriate formal context for determining the better algorithm in this context.

As for O notation, it is an interesting tool but one that has no application within any realm of actual programming in which I have worked, and I have never bothered to learn it simply to dazzle people in algorithm-based interviews (perhaps because I do more nuts and bolts type work rather than optimization).

From the perspective of theoretical computer science, the interviewer was correct. I'll try to sketch out why.


1. In the initial probing for the upper bound, there is no point to grow faster than 2x each time

If we double the probe each time, we'll find the upper bound in O(log N) time. Then, we'll need O(log N) additional time to find the real answer. That makes the entire algorithm O(log N).

Suppose instead, in the initial probing we grow the bound faster, say by squaring each time. We'll find the upper bound faster, but we'll still need additional O(log N) time to find the real answer. So, we didn't really make the algorithm (asymptotically) faster - it is still O(log N).

(I glossed over some details in the explanation, but even if you work out the math exactly - which is not that hard to do - the conclusion holds.)


2. There is no point starting from a number greater than 1

There is no way to pick a "good" starting number - should it be 1,000? 1,000,000,000? 10^100? (10^100)^100? You might as well start from 1. That way, you guarantee that you'll find small numbers fast and large numbers still in an asymptotically optimal time.


As someone with fairly strong theoretical computer science backgound, I can see the intended meaning behind the interviewer's question and answer. But, it is a theoretical question. There definitely are a lot of highly valuable software developers out there who couldn't answer it.

Given that is a theoretical question that you are attempting to fit into an actual algorithm to ostensibly solve a real problem, doesn't the actual performance of the algorithm matter? I can see that within the context of theory of computer science there may not be a difference between the speed of the two algorithms, since both are "asymptotically optimal" (a term I'm not sure I entirely grok), yet within virtually any defined set of random numbers less than infinity the algorithm I provided will perform substantially faster.

I suppose I'm at a loss for words, since as a seasoned software developer without a deep background in theoretical computer science, it seems that I am being told to disregard my intuition based on experience in favor of a theoretical model that seems to ignore actual problem sets. Am I missing something?

I made a python script to time the different approaches:


AFAICT, the parent and the interviewer is right because both methods run in roughly the same time because the time of the binary search is orders of magnitude greater than the upper bound finding part. I might have made one or more mistakes though.

If I have time later today I'll extend your snippet, but my inclination is that the differences in speed become apparent only with very large numbers. I still suspect my algorithm is about 40-50% faster if you start with a googol.

It seems that the problem involves two parts: 1) To find an upper bound 2) Then divide the remaining region in halves until the number is found.

The first observation that I have is that given that the secret number s is chosen, the first step can be completed arbitrarily quickly. One could use a function that rises arbitrarily fast. Imagine for example the function taking k to the Ackerman function A(2,2,k). That rises so fast it's incomprehensible, but really one could easily produce a function which rises faster still (the algorithm that picks s first!). The problem is, though, of how fast a fixed algorithm is for random s. If s is truly chosen at random from the positive integers, this leads to problems. Fix your putative algorithm. Suppose for the moment that it starts at 0 (it is not going to matter where it starts) What is the probability that the kth number that your function spits out is less than a random integer? 100% After all, how many integers are greater than any given integer?

Therefore, no growth function is any better on average at finding the upper bound than any other. Therefore step 1) is an insoluble problem. The problem should have been specified in some other way in order for it to make sense.

However, the second step involves log_2(n) time (in the worst-case-scenario and still O(log n) in general) where n is the upper bound --the output of step 1-- which means that the time to complete the algorithm is (Time of step 1 to find n) + O(log n). IF the problem made sense and it was the case that step 1) were soluble, then it would matter how fast step 1 is countered by the degree to which step 1 tends to overshoot the secret number --because overshooting by k has the penalty of log(k) extra operations.

Is there are framework in which question 1 makes sense? It would make sense if there were a given probability distribution on the integers (a function on the positive integers whose sum over all integers = 1, for example choose the function f(n) = 6/(n^2 * pi^2)) A probability distribution gives you a way of answering the question: "what proportion of the positive integers are greater than k?"

Excellent response. I think the framing element that was missing is if the random numbers were truly random.

My intuition says that they should almost always run at about the same time if you don't know anything about the distribution of guesses. Your algorithm has the advantage that it will find an upper bound for the number much faster than the interviewer's algorithm. HOWEVER, having found that upper bound, your algorithm will probably be much farther away from the actual number than the interviewer's, so you have to do that much more narrowing down. What it comes down to is being lucky that you're close to the number in your initial guess, otherwise, you're still talking logarithmic time to either find an upper bound or (in your case) lower bound for the number.

This was my conclusion, that although the two approaches had the same average big O time, my intuition said it was somewhat faster to start from some number larger than 0.

In retrospect, I might have mentioned this and then gave the interviewer's preferred answer in code, just to keep things simpler.

> Hmm, I'm not sure I like the idea of intentionally trying to steer the candidate off on a tangent. It feels like a trap.

And, yet, it's quite a realistic model of what happens in meetings and presentations all the time.

> In an interview, the interviewer literally has all the power, and saying "no" or refusing to answer a question posed by the interviewer seems rather difficult.

You could say the same with regards to managers or other higher-ups in real workplace environments. It's an important skill to be able to say no, or deflect gracefully.

In this situation, saying "I'm not going to answer that question" is the wrong response. Something like "that's an interesting question, but it will take more than 5 minutes to answer. I'd be happy to go into more detail later if you'd like." is.

It's a realistic model, sure, but the stakes aren't the same.

In a meeting or presentation, you have a subject and an agenda and many people present who expect you to cover them.

In an interview, it's one-on-one. If the interviewer asks you A, then stops and asks you B, there's no reason not to move to B. If the interviewer is suddenly asking about B, they must want to know about it. There are no other stakeholders present who might care more about A. You didn't even know you were going to be talking about A until a few minutes before!

It's an important skill to be able to say "no" and stay focused on a subject. But this is a shitty test for finding out whether a person has that skill.

If you have to interact with customers at all, this is a very realistic situation. The candidate would get points for following up on the tangent question after demonstrating the ability to control the flow of the conversation.

That may not be key for all positions, but for more senior roles, and all roles which are predominantly customer facing, it's absolutely critical.

I disagree. There's no goal here.

Being able to say "no" is important, but so is knowing when to say "no" and when to say "yes".

If somebody tries to drag you onto an irrelevant tangent in a meeting, that's when you should say "no". If somebody is talking to you one-on-one and you discover that they actually care about something different than you thought, that's when you should say "yes".

The problem with this scenario is that it pretends to measure a person's ability to say "no" all while giving them no reason whatsoever to actually say "no".

If you want to test a person's ability to say "no", you have to put them in a situation where that's actually the correct move.

> And, yet, it's quite a realistic model of what happens in meetings and presentations all the time.

Yes, absolutely. In a real work environment where we all know each other I would not hesitate to shut down a conversation that takes the discussion off course.

An interview is not like a real work environment at all. It can try to be a simulation, but it is still just a simulation where the candidate and the interviewer may not know each other very well. Maybe it's my southern upbringing (a topic of much mirth in my office), but I would consider pushing back on a stranger I am trying to impress to be somewhat rude. I have noticed that people out here in SV tend to be more aggressive than I am used to.

I think it depends on the job. If I'm in project manager or manager mode, I might say "That's not relevant," but if I'm wearing my developer hat part of my job is providing information and so I'd be more than willing to jump down the rabbit hole.

The OP doesn't give an example of these questions.

If you're explaining the game of 'Go' to me and I stop you and say 'Tell me about a time you achieved success' then I would expect 100% of candidates to stop talking about Go and start answering the new question.

On the other hand if I stopped you and asked 'Why do you think the counters are black and white?' I expect 100% of candidates to give me an answer that's fairly short and then continue with their original answer.

I can't think of a single question that would separate people into two groups.

There are definitely questions it that can discriminate this. Sometimes it will take a 2nd or 3rd question to be clear it's a distraction.

One example is a candidate that was talking about residential firefighting. I asked them about halon gas as a way to fight with quite a bit of curiosity, and they shut me down. I've learned to trust my insights, because I've seen them confirmed in other ways throughout the interview--it builds a pattern. When it doesn't fit the pattern, I am open minded that it's a fluke.

Ultimately, I think the "trick" nature of this is over emphasized by my blog. The single most telling factor is whether candidates can clearly explain something in essentialized form--that alone is difficult for most people.

I would never, under any circumstances, tell my interviewer to "stay on topic." How should I know what he believes to be relevant? If he no longer wants to quiz me on my abilities as a developer but would rather discuss the airspeed velocity of swallows, I would assume that he has a reason for doing so, and I would gladly share with him with my limited knowledge of avian aeronautics.

Also, the trap question could easily have the opposite "right response" as it does in the post and still be defensible as something important to learn about a candidate. Another interviewer performing the same test sequence might want to see if the candidate can change subjects quickly, roll with new circumstances, and not get flustered or stuck on a single, obsolete outcome.

"In an interview, the interviewer literally has all the power, and saying "no" or refusing to answer a question posed by the interviewer seems rather difficult."

If you feel like the interviewer has all the power in an interview, then it'll be difficult to negotiate your salary. You'll do things like give a concrete number when they ask you what your salary was at your last job.

The only time I would feel like an interviewer has all the power over me is if I was a new grad with no work experience.

An interview is a two-way street, you're trying to find out if you want to work for them as much as they're trying to find out if they want to hire you.

Doing an interview (specifically a tech interview in this situation) and negotiating salaries after you have an offer are two completely different things. I would fall for the trap, but I can (and have) negotiate a really great deal for myself in the offer phase.

The whole interview process is an implicit negotiation over salary.

They refer to the "leader" star candidates as the ones to say no, which makes sense.

Typically when hiring upper level managers you are interviewing someone who is going to be your peer - not someone who will be below you. Part of being a good leader includes pushing back on the people who are going to be your peers, if it means interfering with your tasks.

I have to agree. The question hinges on how the interviewee interprets the game being played in the interview. The interviewer seems to be offering the original instructions (explain something to me in five minutes) "out of character" and then gets into character and starts trying to undermine his original instructions. You're not really learning whether they can handle a meeting with interrupters, or whether they can figure out your silly games.

I loathe this kind of question in HR interviews as well. The far more common one around this way is for the HR staffer to just 'turn' on you halfway through the interview to 'see how you deal with conflict'. Thing is, that's really unnatural, and people do not do this in the outside world. I've worked in tech support, as a medical tech, with adults and kids and autistic kids, done phone surveys, done general customer support... never have I ever had someone 'turn' once I'd built up rapport with them. Sure, you could argue that they must be out there, but if so, they're such an edge case that it's pointless choosing on that basis.

I've also got to agree that 'teaching the uninterested' is hard for someone who likes to do the very thing he's asking.

Job interviews are nothing like the workplace for the interviewee. Things like silent time can be death - I've had interviewers ask things like 'take as much time as you need to think before answering' and then getting annoyed because I was thinking for all of 20 seconds...

"Leaders have the guts to say no." Are you hiring a leader or an employee? In my experience leaders tend to make poor employees and employees tend to make poor leaders. If you're looking for leaders don't expect many of them to walk through the door and sit through an interview. They're off doing something already.

When I first learned about this question, I thought this "trick" part of it was the most interesting. The more I've asked this, the less I care about distracting candidates. So many of them fail even to explain the basics clearly left to their own devices.

The interviewer does not have all the power. Any good interviewer knows this, and finding out whether the candidate knows this can be indicative of the candidates maturity, perspective, confidence, and leadership abilities. Not every position requires these, but some do.

"Don't worry about it. It's not important to the objective of getting you to understand X."

> It feels like a trap.

Reality is filled with traps.

> steer the candidate off on a tangent

Customers, coworkers, managers, do this intentionally or not, maliciously or not.

Any good candidate can do the technical job. Great candidates can survive and thrive in the work place.

> Customers, coworkers, managers, do this intentionally or not, maliciously or not.

None of these situations are the same as an interview. If you're providing an explanation at the behest of the interviewer, why not also depart on a tangent, also at the behest of the interviewer?

If you're explaining the value of your software to a prospect, why not also go off on a tangent at the behest of the prospect.

The role whose function an interview most resembles is that of a sales person. Having been in hundreds of sales meetings, I can say with total conviction that the ability to direct the conversation and deflect tangential questions is absolutely critical to being successful.

That said, every role doesn't require that skill, but OP specifically said that it's only for more senior/customer-facing positions.

Giving credit where it's due - this is a famous Google interview question. http://online.wsj.com/article/SB1000142405270230491110457644...

I actually heard this question before Google even existed. It's not my original idea either. This is an old Microsoft interview question, and I would imagine it predates them too.

I ran into this question at Novell in the early 90's. I answered it by giving a detailed description of Issac Asimov's [fictional] theories of Psychohistory (from Foundation).

I got the job. But I doubt my answer was the reason why. But it did get chuckles from everyone in the room. I never ran into this type of question again. I kind of wish i had though. Lots more sci-fi to run through.

I'm sure it predates Novell too.

Would love to hear more about your answer to the fictional theories of psychohistory. I have not read the Foundation series in a long time, and I've never quite understood the predictive mechanism, how possible Asimov actually thought it was, or the wrinkle introduced by the Mule.

From http://en.wikipedia.org/wiki/Psychohistory_%28fictional%29:

Psychohistory depends on the idea that, while one cannot foresee the actions of a particular individual, the laws of statistics as applied to large groups of people could predict the general flow of future events. Asimov used the analogy of a gas: an observer has great difficulty in predicting the motion of a single molecule in a gas, but can predict the mass action of the gas to a high level of accuracy. (Physicists know this as the Kinetic theory.) Asimov applied this concept to the population of his fictional Galactic Empire, which numbered a quintillion. The character responsible for the science's creation, Hari Seldon, established two axioms:

1. that the population whose behaviour was modeled should be sufficiently large 2. that the population should remain in ignorance of the results of the application of psychohistorical analyses

I believe we are already laying the "foundation for this study. Look at the market. The foundation of the market is us - our consumption (which I believe is ultimately unsustainable - but that's another discussion). At it's core, that's what the market is all about. Right now I suspect Goldman (and the other investment houses) have stopped trying to predict the market. They are trying to control the market. Which leads to many of the problems we have now.

Without accurate data, predictions, you can't completely control risk. So risk remains.

Anyway to answer your question; I just repeated the theory of Asimov and argued why I thought the theories of psychohistory were already in practice. Which of course they were, since everyone was trying to predict the course of the market; which meant predicting the course of the herd. So if you studied people (all of the people), you could win in the market.

But much of the market has changed in the last 20 years. I believe, today it's more about control then prediction.

Hmmm. But the Mule operated outside the Seldon plan.

Psychohistory involves predicting the effects of large numbers of people and assumed that single individuals could not significantly change the future of the galaxy.

Without giving too much away, The Mule was a unique being who could not have been predicted, who could significantly change the future of a whole galaxy.

The Seldon Plan did have contingencies for this kind of thing, hence the Second Foundation novel.

Interestingly enough some historians believe in the central premise of psycho-history, that the actions of a large group of people are inevitable. Ian Morris touches on it in "Why the West Rules - For Now"

I'd bet it predates the concept of the interview. In the Google article, it's not explained in the form of an interview question; Cindy characterizes it as insurance against wasting time. This is the kind of thing I'd expect to see mentioned when reading about English coffeehouses or French salons.

Yes, I ran into this at Microsoft in the early 90's, and it wasn't the first time I'd been asked to do this in an interview.

I'm just gonna leave this here http://throwww.com/a/1sx

Above click-bait (meme-bait?) links to a sarcastic "The Definitive Middle-Management Guide to Conducting Interviews" post.

> Pick any topic you want: a hobby you have, a book you’ve read, a project you worked on–anything.

Hopefully there's more guidance than this, because I feel like I'd freeze up and start "um"ing for five minutes trying to decide the best concept to explain. Maybe this says more about me than the exercise, though...

That's exactly the point. The ideal candidate presumably has a number of ideas ready to go - the question is very similar to other interview questions and you should already be preparing to talk about your hobbies and interests. The question ensures the candidate can think quickly, pick a topic they know about, and talk about it coherently. If you can't do that, you're probably not a good fit for the team. Therefore, the question is an excellent interview question: it identifies those people who are very passionate about <something>, who are organized enough to explain it on the spot and who can interact well while teaching.

Now, to the point about you: you should practice this. Being good at talking about your hobbies and interests in technical detail while explaining clearly is an extremely valuable skill. Learn it.

When this topic comes up I always marvel at the _intellectual_ shortcuts people take to justify the _practical_ shortcuts they take to simplify the hiring process.

Working with someone is the only way to evaluate what it will be like to work with someone. Looking at their work is the only way to evaluate their work. Tautology is your friend in the hiring process. There is no royal road to hiring great people.

With regard to "you should be prepared to talk about your hobbies and interests" - Great people are (almost by definition) not interested in the particulars of your interview process. In fact, if they actually are great people you'll be courting them, not the other way around, and they'll be bringing their own ideas to the table instead of sweating over whether they're conforming to your preconceptions.

I dunno. What if my non-professional hobbies are controversial, or simply derided? I see no reason prospective employers should know that I'm a socialist or enjoy anime conventions, and many of them would almost certainly disapprove of one of those two.

I was asked what my hobbies were when interviewing for a job. I replied that I was currently working through reading books that had banned for various reasons. When asked what that last book I read, I replied "Atlas Shrugged", and explained the premise, story, and conclusions of Ayn Rand.

The interviewer hated Ayn Rand but still hired me.

Explaining and articulating why you are a socialist and the conclusions that lead you to the view is exactly the purpose of the question.

Edit: I think I hold exclusively controversial hobbies / books / opinions. I would love this question so much if I ever saw it in an interview. Controversial topics seem to be perfectly suited to this question.


The point of an interview is two-fold: the company is looking to find a good match for an open position, and the candidate is looking for work. Neither of you wants to enter an agreement that will turn sour.

It is a reasonable position that if you have no interests, or hobbies, or any read books at all that you are comfortable talking about with your employer, that you are likely a poor fit for the company. The topic does not have to be non-professional, either. Pick something that relates to the job if you must.

Isn't about half the world's population somewhat socialist? Or fans of anime? Those two examples you picked are, in my opinion, absolutely ideal topics to answer this question with. Why would you be so afraid to talk about them?

> hobbies are controversial, or simply derided

I think that answers your question.

Look, you're asking someone to walk into an interview, with people they do not know, and lay out a portion of their personal life for examination, without any idea of how that information may be used against them. That's pretty unfairly tilted in favor of the company.

I, for one, do not discuss my private life in depth in interviews - it's not the company's or the interviewers business to know that, beyond certain legal issues.

I may choose to discuss at some point in the future when I better know the person to whom I speak, but until then, it's strictly a professional relationship.

> That's pretty unfairly tilted in favor of the company.

You seem to be assuming that the company's goal is to find a reason to reject someone. That's not correct.

If anything, it's tilted in favor of candidates that have the same hobbies as interviewers.

No, my assumption is that a potential employer has no right to know anything about me outside of professional qualifications or what may raise legal issues (convictions, credit rating [iffy], or conflicts of interest). My personal life is strictly off-limits until I get to know them.

Look, I know it sounds confrontational, and I don't go into interviews expecting a hostile environment. But I also don't go into interviews expecting to speak of anything other than things directly related to the business.

I would be very uncomfortable if asked to speak about anything not directly related to the business or business environment there.

I'd actually speak comfortably about such things, provided the interviewer first shows that they are a good-natured and tolerant person working in an office environment where diverse views and interests are welcome. I as a socialist have no objection to working with one anarcho-capitalist, only to working with an entire company culture that assumes anarcho-capitalism to be The Right Answer. I likewise have no problem with someone who thinks anime is boring (90% of it is crap, after all), only with an entire company culture in which having "geeky" interests other than programming is viewed as childish, immature, or unprofessional.

(After all, I think that leaving work at 6:30PM to go to a Haskell Users' Meetup at 7:00PM where you will drink sugary, caffeinated soda and/or beer, eat bad pizza from a corporate chain, and watch an hour-and-a-half presentation on a programming and theorem-proving suite that is perpetually unready for use on machines with less than 8GB of RAM is downright insanely messianic language fanboyism. That doesn't mean I didn't go right along and watch the presentation to be sociable about it and to give everyone their time to make their case. Hell, it doesn't mean I didn't have a good time, even if I left after my coworker's presentation because I didn't want to stay until 10:00PM to watch a theorem-proving presentation I couldn't understand.)

Personality is certainly a legal deciding factor in hiring someone for a position in a company, especially in at-will employment states.

It is illegal for a company to not hire on undue reasons such as race, religion, political affiliations, etc., but you are entering into an employment relationship, and it is not unfair to understand more about the person you are paying to work with.

The entire United States is at-will employment. Some states forbid "union shops", but nowhere in the USA will you receive a permanent contract like you would in Europe that stipulates you cannot be fired without reason.

A large part of interviewing is gut feeling about someone. If you think their personal life has a number of trite aspects, it's not going to do wonders for their chances.

Which is still unfair.

> Why would you be so afraid to talk about them?

Presumably because you want the job. You wouldn't want to talk about them for the same reasons you wouldn't bring up religion or politics or any other hotly contested subject.

I like Anime, I watch My Little Pony, but I wouldn't bring either up in an interview. Why? Because I know what most of the rest of the world thinks of me with just those two statements. I have MLP shirts, my wife knows people that said 'If I saw a grown man walking around with one of them on I would take my children somewhere away from that pedophile.' That is basically verbatim, with no exaggeration. I am not ashamed of my interests, but I am not mentioning them in an interview.

Of course, I'm also not looking for a job to stand in for a social club either. The only 'fit' I am interested in is can I do the job and are my co-workers not idiots.

My Little Pony was going to be the next item on my list after "anime", actually. It's exactly the kind of completely harmless thing with nasty social stigma I was thinking about.

> It is a reasonable position that if you have no interests, or hobbies, or any read books at all that you are comfortable talking about with your employer, that you are likely a poor fit for the company.

Really? I dunno--I always saw employment as more of a business transaction, and I don't give a damn about the personal lives of those I do business with.

That's extreme. You spend over half your life at work. It is personal. The most popular employers make an effort to contribute to employee's personal lives.

> You spend over half your life at work

Well, that depends. 40 hours a week out of 168 is less than 1/4, but it's certainly true that you spend at least half of your weekday, waking life at work. But more pertinently, it should be time that's set aside for work. I don't know why what we do outside of work should even be a factor, or why I should have to share the cultural values of my coworkers. It comes dangerously close to discrimination.

"Really? I dunno--I always saw employment as more of a business transaction, and I don't give a damn about the personal lives of those I do business with"

Well, I think communication is affected by personality "type". So people more "similar" communicate more effectively. If someone is not comfortable talking about anything except work, that says a lot about that person. If what it says is good or bad is another question, but to me it sounds like a boring human being ;)

This is a tangent, but there are several segues you can use to get from anime to a generic technical discussion. Here are my examples:

- I wrote a scraper for MyAnimeList.net to an sqlite3 db in order to build a mobile website.

- I wrote a shell script that i keep a copy of in each folder for each anime series i watch. When the script runs, it parses its own name as a number and adds one, so that i can easily keep track of what episode i'm up to.

I'm sure there are ways to turn almost any controversial hobby into something technical and demonstrable. Even if it's not something that you've built directly - Do you use the MAL Updater? Have you tried out Vocaloid? Using a really interesting playback method (hi10p, lavf, madvr, ...)? You could explain how they work.

From what I understand, Jason Garrett-Glaser (DarkShikari) got interested in video encoding through the anime scene. He's now the lead developer on X264.

Absolutely (although you'll get told off for spelling x264 with a capital X). The `--tune touhou` option is a big giveaway - fascinating to see how an anime-subculture game had such a profound effect, but it's obviously a useful test case for the encoder.

My other favourite example in the same vein is Avery Lee of Virtualdub fame (with EA, last i heard?). He maintains some fantastic software and an enthralling blog, and it all comes back to Sailor Moon.

Ah, but the thing is: I don't have any technical projects related to anime. I currently have two technical projects on slow burn, but neither is anime-related.

One of them is a research project, so I can always talk about that at the risk of coming across as single-minded.

The other is a bit of software I'd like to turn into an on-the-side lifestyle business.

I mean this question honestly: are you American? Because back in the States, mentioning that I'm a socialist would bring the reply, "So why are you working in private industry instead of for the government? Are you here to infiltrate our business?", and things of that nature. At that point I'm not explaining anything, I'm in a debate over whether left-wingers are violating our own principles by ever working in a private, capitalist business (the proper answer is, of course we are, but nobody living under capitalism can actually boycott all capitalist enterprises and remain alive day-to-day). At that point, I've failed the interview by dragging myself off-topic and into an argument.

Point is, yes, outside the US, and to a lesser extent the rest of the Anglosphere, approximately half the world has some kind of left-wing views. Probably as many people have a hobby someone might embarrass them about. It's just not very common in polite company, in most cultures (where I live now it's downright common), to bring up this kind of out-of-work stuff as part of a job interview.

As to the anime, I once mentioned in a daily SCRUM meeting that I wanted to get done a meeting with my team leader before 5:30 because I wanted to get to an anime club at 6PM. A senior colleague, who I really do like and admire most of the time, said that Rule 1 of Anime Club is never to talk about Anime Club. This man was a professional software engineer, working in a software company, who had himself sold bootlegged imported anime back in the '90s as a side gig, and here he was engaging in geek-shaming.

That was one of the many things which made me feel deeply, deeply uncomfortable in that workplace, the other one being the fact that many people there openly and enthusiastically brought up their right-wing libertarian views (without my prompting, this was between other person 1 and other person 2) during work hours.

Overall, the various little details I hadn't detected at the interview eventually added up to a gestalt feeling that the place had the company culture of a particularly right-wing frat-house. I didn't last long there before leaving... on good terms with everyone, but feeling uncomfortable and ashamed nonetheless of leaving a job too early-in.

Hmm.... which means that for small companies like that one, you've actually got a very good point. If I bring up something controversial or unusual and the interviewer can't accept that I have views and hobbies outside work which he/she deliberately asked to hear about (provided I don't go into some boring technical lecture on an obscure topic in Computer Science I like or a physics discovery I don't actually understand nearly as well as I think I do), then it's almost definitely not a good match of a place to work for me. The model just breaks down when we're talking about large companies, or places that have a lot of good going for them outside their company culture.

>here he was engaging in geek-shaming.

No, he was making a joke about Fight Club. But if you are determined to feel persecuted, I'm sure you can find a way. The anime club at my workplace meets weekly in a conference room to use one of our projectors. Several coworkers have figurines or wallscrolls in their offices. And yes, this is in America.

Hi. I did recognize the joke about Fight Club at the time. But please do trust me, the tone and context made it a mild form of geek-shaming. His effective statement was, "Yeah, I liked that stuff too when I was a kid."

Further instances included people, starting with the same man, explicitly stating that they preferred the X-Box 360 to the Nintendo Wii because the Wii is childish. This was around the time "Elder Scrolls: Skyrim" came out, so there was a bit of a buzz about the new game release. I had mentioned being excited for the new "Legend of Zelda" game, which was contemporaneous.

I wasn't "determined to feel persecuted". Remember, if I had felt persecuted when interviewing, I would never have taken the job. I had really been excited for that job, actually.

I had never expected my coworkers to share my out-of-work hobbies, but I had expected that if the topic came up in casual conversation, I wouldn't be labeled childish or immature for what I like doing outside of work (particularly since I was, at that time, the youngest person in the office... but still old enough to be a college graduate who can legally drink working a salaried job and living independently).

A poster further down has mentioned "My Little Pony" (which, thank God, I didn't even know about back when I worked at this office). It's another fairly good example. If you ever reveal to most people that you enjoy that show, they will say to your face that you're some kind of manchild JD Salinger character, or someone with severe gender identity issues.

Which brings us right back to the issue that you should not be talking about this stuff in a job interview unless the interviewer has actually established that they are a good-natured and tolerant person who cares more about how you answer than what you answer. And I would hold that the same standard should apply to being a far-right Tea Party member, or having a cockfighting hobby.

I had never expected my coworkers to share my out-of-work hobbies, but I had expected that if the topic came up in casual conversation, I wouldn't be labeled childish or immature for what I like doing outside of work

That sounds reasonable. But I wonder if it's always true that you can't label anyone? What if someone mentioned that they spent all weekend doing a <super childish activity> :) Would you not label them as childish? (I'm not saying anime is childish)

More to the point, I think it's fine to express disinterest or even dislike other peoples hobbies etc, as long as it's done in a non-hurtful way. I don't think that's labeling people. It's just finding common ground. It's a way to stop people from going on about things you know you have zero interest in hearing about.

There's friendly environments, and there's professional environments. You can label freely in a friendly environment, but you have to actually get to know someone socially to create that. You don't label in a professional environment.

When someone asks you to talk about a hobby or book that you feel passionately about, it's probably wise to stay away from politics and religion.

Although I think it would be a great near miss to find out I was going to suffer religious/political persecution before accepting a job.

My interview at that workplace included no questions about politics or religion. However much they may later have made me feel uncomfortable in their company culture, they were experts at their craft and consummate professionals.

It took me about a decade to realize this, but it's a lot more fun to work for companies where your quirky hobbies fit in, rather than companies where they would look down on you because you think that casual fridays mean "sexy pichaku".

> and you should already be preparing to talk about your hobbies and interests

What!? How is that in the slightest bit relevant?

I suppose it depends on the person and on the job. For me, I list my hobbies and interests on my resume. So it's clearly relevant, as the interviewer has a copy of my resume and I had better be prepared to talk about what I wrote. For my job, my hobbies have always been relevant. I've been through about 15-20 interviews in my life so far and my hobbies have been a topic at every single interview. It's tough for me to imagine a job where these topics aren't relevant.

I appreciate that this may not be universally true, but for me it's mission critical.

OK, if you're applying for programming jobs and programming is also your hobby, then you have a point. I put my programming hobby projects on my resume too. But that's it.

If my hobby is playing bass in a death metal band, or volunteering for the LGBT community, or racing motorcycles, or political activism, it's hard to see how that's relevant at all. All I accomplish by putting that crap on my resume or talking about it in an interview is giving a prospective employer an opportunity to discriminate against me based on irrelevant crap[1]. Because believe it or not, if someone has diametrically opposing interests but they're willing to be professional about it, I'm willing to be professional about it too.

[1] Admittedly, if you're applying to work in a music store, or for a LGBT nonprofit, or a motorcycle shop, or a political campaign, those hobbies become relevant, and your programming hobby becomes irrelevant.

Funny, I put my hobbies on my resume and nobody has ever asked about them.

Depends on your industry. It's usually quite relevant in the video game industry, for example (and usually for the wrong reasons, but it always makes for some interesting interview discussions...).

I assure you I can ably speak extemporaneously about anything I grok in technical detail when required, but I am speaking about the simple act of choosing which thing to talk about.

I would probably spend a lot of time trying to decide which area was appropriately work-safe and which was not. For instance, I would never discuss any of my table-top gaming hobbies unless I knew them for some time. I wouldn't discuss any theatre-related topics, either.

I could probably do an hour or two on some technical topics, without causing too many suicides, but I would only consider those if they were relevant to the job I was seeking.

An important thing to keep in mind is that it's not that you are innately incapable of answering the question, you just may not be able to do so presently, which is why it's a great question.

People who are in a rut, or carrying a lot of baggage, (among others) are going to have trouble answering it, and they're probably also going to have trouble adjusting to a new position. Not to say that you are, but it would register as a possibility to an observant interviewer.

People who are currently active and engaged will not have trouble coming up with something, and they probably won't have trouble getting their point across in 5 minutes. You might actually have trouble stopping them after 5 minutes because you're engaged with what they're talking about. This is a good sign of someone who wants, and is ready for a new opportunity.

That said, I've used slightly constrained versions of this in interviews, like picking up on a side comment/complaint someone made early in the interview. It's a good way to really see someone hunker down and think and express themselves without putting them on the spot like a test. Note that you inserted the idea of the "best concept" on your own, you've made it into a test which implies a right answer, when it isn't. Things like that are warning signs when it comes to adding a new personality to a creative team, and why this style of question is so revealing.

You're saying that when someone freezes up in an interview it predicts that they will have trouble adjusting to a new position.

Simply put, why should I believe that? Can you convince me that this is not simply like any pseudodiagnostic personality test or tea-leaf reading?

"pseudodiagnostic personality test"

What else do you think an interview is?

Supposing I had just finished a Ph.D thesis, that would probably be the first thing to come to mind. The problem, though, is that it would take far longer than 5 minutes to explain. Supposing I had just finished a paper in some scientific field, this would still probably take longer than 5 minutes to explain. Even a basic paper, like "this paper talks about the results from these guys and why they are wrong because they incorrectly used this statistical tool" would take a while. Every good presentation at science conferences has to make an assumption about the audiences' general knowledge and start their presentation at the audience's inference level and connect it to higher levels until they get to the conclusion. If your result is more than one inference level above even other experts in the field, you're not going to be able to explain it to any of them in 5 minutes, let alone this tech-company interviewer whom you know nothing about. Could Andrew Wiles explain his proof to anyone in 5 minutes when it came out? Not even Feynman could explain electricity and magnetism to a layman.

That said, I guess explaining a (known) subject like how to cook scrambled eggs is fine. The interviewer learns nothing, but you passed the silly question. If asked this at an interview for a job I really wanted (if I was lukewarm I'd join others in walking out), I'd probably talk about some trivial feature in Clojure (lazy evaluation, say, or more generally the three main purposes of real non-C macros) that Mr. Interviewer probably has never heard of. I have to assume Mr. Interviewer can program but if that assumption is wrong that'd be enough to make me walk out even if I wanted the job.

>> Supposing I had just finished a Ph.D thesis, that would probably be the first thing to come to mind. The problem, though, is that it would take far longer than 5 minutes to explain.

Of course it would take more than 5 minutes to explain fully. Part of what this question is designed to test is whether you can give a 5-minute version of something more complicated.

If you can't do that, how are you going to, for example, explain why you want to use technology X instead of Y? Assuming the listener knows less about X and Y than you do (whether they're a manager or a fellow programmer), you have to be able to summarize the differences.

This is really an important communication skill.

After reading your comment, I went to arxiv and picked the first paper in High Energy Physics - Lattice, of which I know nothing about. http://arxiv.org/abs/1210.1053 Hey, it's only 4 pages.

Reading the title: "Lattice measurement of α_s with a realistic charm quark." I know what a lattice is, I don't know what sort of measurement they intend to make on it, I have no clue what alpha_s is, I know vaguely what quarks are but don't remember the differences between say a charm quark and a strange quark. I don't know what makes a quark "realistic" or not.

Abstract: "We report on an estimate of α_s , renormalised in the \overline{MS} scheme at the τ and Z^0 mass scales, by means of lattice QCD. Our major improvement compared to previous lattice calculations is that, for the first time, no perturbative treatment at the charm threshold has been required since we have used statistical samples of gluon fields built by incorporating the vacuum polarisation effects of u/d, s and c sea quarks. Extracting α_s in the Taylor scheme from the lattice measurement of the ghost-ghost-gluon vertex, we obtain α_s^\overline{MS} (m_Z^2) = 0.1200(14) and α_s^\overline{MS} (m_τ^2) = 0.339(13)."

No idea. Perhaps the introduction will be enlightening...

Hey, some progress. The paper appears to be using data from the LHC experiments that have been all over the pop-sci news for the last few years. Section 2? Math, data... Hey, section 3, conclusions. So they have given a measurement of alpha_s from lattice simulations, specifically an improved method for lattice simulation. Googling says alpha_s is the strong coupling constant, and hey, I've seen the fine-structure constant before... alpha_s has to do with "asymptotic freedom". Is there a 5-minute intro to the point of trying to measure alpha_s? Is there a 5-minute intro describing measuring alpha_s with lattice simulations as opposed to something else?

This whole exercise took me quite a bit longer than 5 minutes and I still don't feel like I understand much of anything. What's the most important part here? I'll probably forget everything I typed down by the end of the day, except perhaps that alpha_s is somehow related to the universal-constant alpha I've seen before. I'm doing this from the perspective of the ignorant person. Could the authors of the paper (or a fan of the paper who read it, understood it, and wants to explain it to me) explain to me what exactly they're doing to a sufficient degree? I mean, such that I have a clue what (if not why) the paper is trying to accomplish in a real sense, what's important about the paper, without needing to understand how they accomplish whatever the goal is, or understand all the math and science details? Probably they could, but it would take a lot more than 5 minutes. It'd take more than 5 minutes just to get the initial definitions out of the way such that I don't have too much confusion over what is being discussed. Is there a 5-minute intro to quantum chromodynamics?

Even Khan Academy videos are usually at least 10 minutes. His American Civics videos provide the best example for my point here.

As for explaining why I want to use technology X instead of Y, this is an entirely different question than the one proposed in the submission, and one that's actually a better interview question. "Tell me about a time you were faced with a choice between competing technologies and how you justified that choice to your superiors." If someone's asking me to explain why I want X over Y, I have three responses depending on who's asking and in what context they're asking in. The first is the rude one: "Bug off, I don't have to justify my decision to you and you're wasting my time / company dollars having me explain something so many inference levels above your present understanding". I don't think I've ever actually used that one, but it's a possibility. What usually happens: "Here's the tradeoffs I'm making, here's why I think these tradeoffs are a good set to make at this point." But this requires I make the assumption that whoever I'm talking to knows something, isn't just an ignorant off the street. Fortunately at tech companies this assumption is fine. Describing superficial differences ("I want to use Python over PHP because it enforces indentation and will be prettier", or "I want to use DynamoDB instead of MySQL because DynamoDB isn't SQL") is useless. You can make a lot of such useless statements in 5 minutes and completely miss the useful ones. Giving an actual explanation of the technologies and reasoning behind picking one over the other, that will take more than 5 minutes, doing otherwise is unfair to the person seeking the understanding. One should not attempt to give explanations like one gives elevator pitches.

The last response is taking the Feynman route and throwing up my hands in defeat, a nicer approach than the first response. "Sorry, I just can't explain things that are so many inference levels above you. I can spend 5 minutes per level trying to build you up to where I can explain this thing you're asking about, it might take a couple days, but I can't just jump in one step from your level to here." I can explain basic lazy evaluation in hopefully less than 5 minutes to someone who has/could pass a programming class, if they're engaged and fulfilling their part of the two-way street that is learning. If they're ignorant and want to learn, they can learn but it will take a while. If they're ignorant and don't want to learn, I have spent hours with people trying to hammer in basic algebraic concepts or programming concepts to no avail (this on top of whatever their professional and licensed teacher is doing).

In the realm of books, if I was asked to explain Data Analysis: A Bayesian Tutorial, how could I even begin doing that with someone whose notion of probability is at best "1/6 chance of getting a 6 on a die roll"? Do they even have a coherent internal model for what "information" is, a concept that is really quite new in human history? I have to start at a level way below where the book is at, and 5 minutes later I still won't be at the book's level and I can't explain the most important aspect of the book. Unless something like "knowing the stuff presented in the book helps you do cool things with computers", expanded upon for 5 minutes, is adequate. Is "helps you learn how reality works", expanded upon for 5 minutes, an adequate explanation for what the important aspect of the Giancoli physics book is?

I suspect our disagreement is more over where our standards of explanation quality are. Maybe you think trying to use a rubber band metaphor for magnetism is fair, I think it's cheating the learner. Maybe you think using shaky analogies that "lead to all kinds of implications" is adequate, I think such carelessness is only poisoning the well.

If you want to know how a candidate communicates certain pieces of information at a job, ask them how they do it. If you want to see how a candidate reasons in an argument, get into an argument. If you don't want to argue directly, help them find something relevant that they dislike and see what structure their rant about it takes. If they don't really dislike anything (or just don't want to take a stand on anything) that's also useful to know. A lot of these interview "tricks" purport to select for certain traits but it's usually a very indirect method at best.

" Take as much time as you want to think it through, and let me know when you want to start."

I think part of the point is that there is no guidance since they're looking for someone who is passionate enough about something to be able to explain it. It sounds like you'll have time to gather your thoughts and it is even seen as a negative if you don't. I'm sure you can come up with something to explain after 5 minutes.

You probably would not get hired.

Actually, people that think about this for a while are the ones I like the most. The people that race right in without thinking about it tend to perform the worst.

One of the very best candidates I saw actually just wrote their outline on the whiteboard from the start. When I asked them a distracting question they paused a second, looked at the whiteboard, and said "Wait a minute, this will stop us from finishing in 5 minutes. Would you like me to answer this or finish?"

You probably would not get hired.

Probably not. But what does that say about this particular technique?

There's the ability to explain something, and there's the ability to perform under sudden pressure.

I would give candidates some period of time (say, 10 minutes, if they needed that long) to select a topic first.

You've scheduled a half-hour with a candidate (or explain why longer), and you're going to sit in silence for 10 minutes just so s/he can pick a starting point for a 5 minute monolog on any topic?

Given the option to talk about anything, I'd be concerned if the candidate couldn't pick something in 10 seconds. Summary of last book read, semantic difference between method calls in C++ vs Objective-C, sewing, recreational ballistics, sociopolitical solutions to poverty, ... something? I could spend the allotted 5 minutes just reviewing topics I could go on for 5 minutes about.

What would you be concerned about?

Giving a spontaneous monologue to someone judging you is something many people actually find quite intimidating, even though some others may find it quite natural. It's something they teach in toastmasters or improv classes.

It's part of social success (and business, from development to sales, is a social activity). There WILL be times when a moment will occur where you must take a barely-formed thought and run with it, taking someone else from zero to competence, in mere minutes; to not do so is to miss a valuable opportunity. Be it making an unexpected sales pitch, explaining a non-obvious technical solution that just occurred to you during a design meeting, discussing last night's political debate, or describing your hobby to an attractive new acquaintance, success often depends on succinct explanations without preparation.

The point of the exercise isn't the content per se, it's the demonstration of ability to present concepts (any concept) clearly, and perhaps convincingly, on short notice.

Yes, it can be intimidating. Yes, it's an unplanned speech to a judgmental audience; such is the real world. There's a reason it's taught as a tool for success. I had to figure it out on my own. Survival and success can depend on it.

Heck, here I am taking 5 minutes, unexpectedly, trying to explain to you - a judgmental audience - regarding a random topic. If you get my point (convincing notwithstanding) then I pass the test. If a candidate can't do likewise on the topic of his choice, I can't expect as much when the topic is not.

It sounds like you're saying that it seems like it should be diagnostic vaguely of "success" or "survival".

Perhaps it might have negative values as well. Part of the trick seems to be to turn off critical thinking for awhile, not reconsidering your assumptions, turning off self-doubt or sounding confident, or being strategically vague. Skills I would value in a salesperson, but not necessarily an engineer.

Since all of these ideas are introspective and the output variable is unspecific I don't see a good way to make a decision about the usefulness of this test.

Given the option to talk about anything, I'd be concerned if the candidate couldn't pick something in 10 seconds.

I'd be concerned if they could. It might suggest they are not all that interested in too many things. Or are hyper-focused on just one thing.

There are two things at work here. Picking something you are interested in, and deciding if you can actually explain it well in five minutes. Figuring out the latter would take me easily more than 10 seconds.

It's not a matter of picking something you can on about for five minutes. It's about be able to explain it to someone with no prior knowledge, and have them understand what the hell you were talking, and what's most important about it, when you are done.

Now that the article is back up, it see it has this:

Take as much time as you want to think it through, and let me know when you want to start.

So another question is, is it better to allow "as much time as you want", or set some time limit in picking the topic?

Practically speaking, if someone is still musing after an hour I think the jig is up, so there's at least some practical upper limit. But how does it influence the candidate to think there is a fixed prep time versus having unlimited time?

Having a thing that you can talk for 5 minutes about and being able to actually _pick just one thing_ under sudden pressure are very different things. I understand the time pressure issues, but understand that you are also testing this other skill of being able to respond with that questions.

It's not "pick a topic to discuss", it's "pick a topic that you can spend five minutes doing a complete lesson on", sprung as a surprise question.

> I would give candidates some period of time (say, 10 minutes, if they needed that long) to select a topic first.

It appears you would not be hired because of your lack of reading comprehension.

The article clearly states that you have as much time as you want to gather your thoughts and it's a bad sign if a candidate starts right away.

The article is down, is it not?

Edit: NVM, the website is back up.

It was down when I was posting, and I went off a shortened version of the question as summarized in another comment.

People late to the discussion may want to consider reading more comments before sniping at earlier posts.

I'm not sure going in to a job interview is 'sudden pressure'. You've often had days or weeks in preparation for that 30-60 minute meeting.

But it's not a common question, and wildly uncommon questions in an interview can cause even great minds to seize. Interviewing for a tech support job years ago was the most difficult interview I'd ever been in, because the manager didn't stick to the script, so to speak. He threw out random questions, completely unrelated to the job, in a rapid fire manner. Just to see if he could throw you off, to see if he could get you to seize. What is your favorite book? I like the Hitchhiker's Gu-What was the last song playing on your drive over here? It was Lola by The Ki-What color shirt are you wearing, without looking down?

You can prepare for an interview. And the interviewer can prepare to surprise you. The sudden pressure is when you're asked an important question that you had no knowledge was going to be asked.

Well, at the same time, I wouldn't be able to do my job if I didn't have the ability to perform under sudden pressure.

There are different kinds of pressure. I went to lunch with a coworker who was very good at dealing with the pressure of running the shipping pipeline. Someone started having a seizure in front of us. I stepped in and dealt with it (ex-neuro) while she was paralysed and unable to do anything but watch in horror.

I'd probably just say, "I'm sorry to have wasted your time--I'm not interested in the position after all," and then get up and leave the interview.

from the post:

"It is amazing how many candidates will not premeditate before diving into this interview question. Once the trigger happy type candidates get going, they don’t have any kind of bulleted list or outline in their head of what they hope to get across. What’s most incredible about this is how accurately it predicts disorganized and non-goal directed behavior on the job. I’ve been over ruled a few times by my manager on a hiring decision, and question was a harbinger of things to come. Conversely, the people that think it through and have a few crystal clear points are amongst the best people I’ve worked with. They are not just easy to communicate with, but get results in their work."

You are supposed to take your time and think about it before diving in. Which is a good tactic for problem solving in general.

It only took me a sec. I was going to explain how to cook the perfect scrambled eggs.

Complete with the tip about putting water in them so that the steam puffs up the eggs to a fluffier consistency?

Actually, the secret ingredient is butter.

And love.

This is universally true.

"Sergey [Brin] nodded his agreement, then asked about my six months in Siberia, casually switching to Russian to see how much I had picked up.

Finally, he leaned forward and fired his best shot, what he came to call 'the hard question'. "I'm going to give you five minutes," he announced. "When I come back, I want you to explain to me something complicated that I don't already know." He then rolled out of the room towards the snack area.

I looked at Cindy. "He's very curious about everything," she said. "You can talk about a hobby, something technical, whatever you want. Just make sure it's something you understand very well."

... I decided to go with the general theory of marketing, which was fresh in my mind because I'd only learned it recently..

I went to the whiteboard and furiously drew circles and squares and unleashed arrows like Legolas. I was nervous, but not very. Sergey bounced on a ball and asked questions that required me to make up things up on the spot...


Later I found out that Sergey did this with everyone he interviewed. An hour wasted with an unqualified candidate wasn't a total loss if he gained insight into something new."

"I'm Feeling Lucky: The Confessions of Google Employee #59" - Douglas Edwards

The submitted site seems to be having trouble keeping up with the referrals from Hacker News, judging by its response time. (And that is amusing for a site called "refer.ly" that is all about user referrals. The site still needs upgrading to work at scale.)

The question is "I want you to explain something to me. Pick any topic you want: a hobby you have, a book you’ve read, a project you worked on–anything. You’ll have just 5 minutes to explain it. At the beginning of the 5 minutes you shouldn’t assume anything about what I know, and at the end I should understand whatever is most important this topic."

I have to say that the proposed job interview question is interesting, and the thought process outline in the blog post kindly submitted here for evaluating answers to the question is also interesting. That made me think of a way to evaluate the hiring procedure mentioned in this blog post--do empirical validation of whether people hired through that procedure really do better work over the course of their career than people hired through other procedures. That's the scientific way to look at what hiring procedure to use.

Here, in a FAQ that should take less than five minutes to read for a native speaker of English, is what is most important about what science has validated on the topic of company hiring procedures. The review article by Frank L. Schmidt and John E. Hunter, "The Validity and Utility of Selection Models in Personnel Psychology: Practical and Theoretical Implications of 85 Years of Research Findings," Psychological Bulletin, Vol. 124, No. 2, 262-274


sums up, current to 1998, a meta-analysis of much of the HUGE peer-reviewed professional literature on the industrial and organizational psychology devoted to business hiring procedures. There are many kinds of hiring criteria, such as in-person interviews, telephone interviews, resume reviews for job experience, checks for academic credentials, personality tests, and so on. There is much published study research on how job applicants perform after they are hired in a wide variety of occupations.


EXECUTIVE SUMMARY: If you are hiring for any kind of job in the United States, prefer a work-sample test as your hiring procedure. If you are hiring in most other parts of the world, use a work-sample test in combination with a general mental ability test.

The overall summary of the industrial psychology research in reliable secondary sources is that two kinds of job screening procedures work reasonably well. One is a general mental ability (GMA) test (an IQ-like test, such as the Wonderlic personnel screening test). Another is a work-sample test, where the applicant does an actual task or group of tasks like what the applicant will do on the job if hired. (But the calculated validity of each of the two best kinds of procedures, standing alone, is only 0.54 for work sample tests and 0.51 for general mental ability tests.) Each of these kinds of tests has about the same validity in screening applicants for jobs, with the general mental ability test better predicting success for applicants who will be trained into a new job. Neither is perfect (both miss some good performers on the job, and select some bad performers on the job), but both are better than any other single-factor hiring procedure that has been tested in rigorous research, across a wide variety of occupations. So if you are hiring for your company, it's a good idea to think about how to build a work-sample test into all of your hiring processes.

Because of a Supreme Court decision in the United States (the decision does not apply in other countries, which have different statutes about employment), it is legally risky to give job applicants general mental ability tests such as a straight-up IQ test (as was commonplace in my parents' generation) as a routine part of hiring procedures. The Griggs v. Duke Power, 401 U.S. 424 (1971) case


interpreted a federal statute about employment discrimination and held that a general intelligence test used in hiring that could have a "disparate impact" on applicants of some protected classes must "bear a demonstrable relationship to successful performance of the jobs for which it was used." In other words, a company that wants to use a test like the Wonderlic, or like the SAT, or like the current WAIS or Stanford-Binet IQ tests, in a hiring procedure had best conduct a specific validation study of the test related to performance on the job in question. Some companies do the validation study, and use IQ-like tests in hiring. Other companies use IQ-like tests in hiring and hope that no one sues (which is not what I would advise any company). Note that a brain-teaser-type test used in a hiring procedure could be challenged as illegal if it can be shown to have disparate impact on some job applicants. A company defending a brain-teaser test for hiring would have to defend it by showing it is supported by a validation study demonstrating that the test is related to successful performance on the job. Such validation studies can be quite expensive. (Companies outside the United States are regulated by different laws. One other big difference between the United States and other countries is the relative ease with which workers may be fired in the United States, allowing companies to correct hiring mistakes by terminating the employment of the workers they hired mistakenly. The more legal protections a worker has from being fired, the more reluctant companies will be about hiring in the first place.)

The social background to the legal environment in the United States is explained in many books about hiring procedures



Some of the social background appears to be changing in the most recent few decades, with the prospect for further changes.




Previous discussion on HN pointed out that the Schmidt & Hunter (1998) article showed that multi-factor procedures work better than single-factor procedures, a summary of that article we can find in the current professional literature, for example "Reasons for being selective when choosing personnel selection procedures" (2010) by Cornelius J. König, Ute-Christine Klehe, Matthias Berchtold, and Martin Kleinmann:

"Choosing personnel selection procedures could be so simple: Grab your copy of Schmidt and Hunter (1998) and read their Table 1 (again). This should remind you to use a general mental ability (GMA) test in combination with an integrity test, a structured interview, a work sample test, and/or a conscientiousness measure."


But the 2010 article notes, looking at actual practice of companies around the world, "However, this idea does not seem to capture what is actually happening in organizations, as practitioners worldwide often use procedures with low predictive validity and regularly ignore procedures that are more valid (e.g., Di Milia, 2004; Lievens & De Paepe, 2004; Ryan, McFarland, Baron, & Page, 1999; Scholarios & Lockyer, 1999; Schuler, Hell, Trapmann, Schaar, & Boramir, 2007; Taylor, Keelty, & McDonnell, 2002). For example, the highly valid work sample tests are hardly used in the US, and the potentially rather useless procedure of graphology (Dean, 1992; Neter & Ben-Shakhar, 1989) is applied somewhere between occasionally and often in France (Ryan et al., 1999). In Germany, the use of GMA tests is reported to be low and to be decreasing (i.e., only 30% of the companies surveyed by Schuler et al., 2007, now use them)."

Integrity tests have limited validity standing alone, but appear to have significant incremental validity when added to a general mental ability test or work-sample test.





AFTER EDIT: A kind comment to this comment graciously assumes I wrote this FAQ only just after when the article opening this thread was submitted. In fact, as was pointed out by a kind reply to that comment, I have prepared this FAQ document in advance, because questions about company hiring procedures frequently come up on Hacker News. I began summarizing the research about six months ago, and other participants here on HN have helped me take this FAQ through several revisions as it reached its current form about two months ago. Questions about hiring procedures come up again and again on Hacker News, and I like to store electrons to conserve keystrokes.

I agree that intelligence and work samples are the most critical things to look at. The trick with work samples is that most people focus too narrowly.

Yes, coding is a critical part, so don't skip it. But so is team communication (no matter how great of a programmer you are, if you won't respond to my emails, I won't think you are a great employee). So are code reviews (if you call people morons for not agreeing with your style, no matter how great of a programmer you are, I won't think you are a great employee). So is mentoring (if you can't explain concepts to people who aren't as smart/experienced/whatever as you, no matter how great of a programmer you are, I won't think you are a great employee).

I could go on. I think it is some of these softer skills that many interview questions have tried (and mostly failed) to suss out. Back to the OP, I can see it being a reasonable effort at experiencing some of the non-coding work requirements.

Much better than "how many ping-pong balls would it take to fill this room" and "design a nuclear reactor for me", both of which have been asked of me in web developer interviews.

As a nuclear engineer I am mildly offended they would ask you that in a job interview.

You mean they don't ask you to develop web sites during job interviews for nuclear engineering positions?

What were the interviewers trying to find out by asking those questions?

The ping pong ball question has been used a lot to see how/if engineers will attempt to give a reasonable estimate with proper caveats. No attempt is auto-fail, as is going into too much detail, and the rest is judged by the reasoning, approach, and if decent upper and lower bounds are given.

I imagine the reactor is similar but also checks if you can say where you are not competent and should defer or delegate.

the interviewer is actually looking for a soul mate.

These look like Fermi problems, they are supposed to check your ability to work with assumptions, and insufficient data. The answer is not important, the thought process is.

I've never worked in consulting, but, so far as I know, the big, MBB consulting firms tend to incorporate most of the advised measures in tokenadult's post when evaluating potential employees. These measures include GMAT cut-offs, GPA cut-offs, very lengthy interviews that incorporate questions like the one discussed here, and they ultimately prefer to hire people who have previously interned with them, and what better work-sample test is there than an internship?

That sounds like a pretty solid vetting process to me, yet there's a lot of pessimism surrounding big-name consulting. I'd like to hear from anyone who's worked there or gone through this process to hear why they ultimately get such a bad rep.

Consulting companies built their reputations on their work in the 60s, 70s, and 80s. They encouraged companies to do things we now consider Business 101 (it was cutting-edge stuff back then though). Several major companies in the 1960s had no insight into their competitors or even a full picture of the market they were in. These were the sort of organizations that collected very little data beyond sales and balance sheet figures - it was like they lived in a "bubble". The pioneering consulting firms popped those bubbles and actually taught businesses how to do basic market analysis, and turn that analysis into business strategy.

If you're at all curious, I'd recommend reading The Lords of Strategy by Walter Keichel, which a (albeit opinionated) history of the consulting practice.

I'm going to try to answer your question but I imagine it's very Anna Karenina-esque: "Happy families are all alike; every unhappy family is unhappy in its own way."

Often the problem is the size of the firm, allowing institutional problems to sabotage otherwise good practices. Instead of recognizing and promoting the things that will improve the firm long-term, they implement good hiring practices only to prevent lawsuits, bad press, etc.

Revitalizing a large company before it dies is a very difficult problem.

I like to see this at the top of every post promoting pseudodiagnostic interview questions.

I have often thought we should have a hash-tag means of labelling some comments or threads. For example the above FAQ would be #hiringbestpractise (or possibly #tokenadulthomerun ). Then this thread would be found if anyone searched HN for that tag, and indeed would rank top of all #hiringbestpractise tagged comments.

Then tokenadult could simply point people to the hashtag page and say enter the right phrase.

I for one would value seeing the top rated comments from HN on any range of given subjects, even several years back


> I like to store electrons to conserve keystrokes.

But re-posting the same stuff over and over does not conserve page space. Maybe you could link to your older comment instead of re-posting it?

I think most people prefer reading it "inline" and not linked.

Tokenadult, please continue reposting.

>Tokenadult, please continue reposting.

That would make certain searches of news.ycombinator.com more frustrating.

Web pages that duplicate other web pages have been around for almost 20 years now (documentation by the GNU project being a notable early example) and even with all of their resources, Google still fails to filter out duplicates a significant fraction of the time.

"I think most people prefer reading it "inline""

How do you know what most people prefer?

Your question could be better phrased:

  Why do you think most people prefer to read it "inline"?
Far less snark, don't you think?

My answer would be: because some of my highest voted comments have been snippets copied from a larger work instead of just linking to the larger work. Perhaps people don't want to open up a new tab, perhaps they don't want to load a new page, perhaps they appreciate keeping the content in context with the rest of the comment thread, perhaps they appreciate keeping the content on HN for "prosperity sake" due to the ever-breaking links of the rest of the web.


Guilty as charged!

""prosperity sake"" (think you mean "posterity"?)

Sigh. Thanks. This is the second time I've been caught with an eggcorn[0]. First "windshield factor"[1], now "for prosperity sake". Looks like I might have the privilege of adding to their database myself this time...

We'll just keep this between you and me right?

[0] http://eggcorns.lascribe.net/

[1] http://eggcorns.lascribe.net/index.php?s=windshield

I certainly prefer it.

Tokenadult, keep posting.

Also, take a page from patio11's book and start selling access to this advice. (and perhaps consulting).

Your comment is in error - the quote starts I think, which is a far less didactic sharing of opinion.

Are you running out of page space?

What kinds of jobs do those papers refer to? How relevant is this research for engineering positions?

The main article tokenadult is talking about is the Schmidt & Hunter paper: "The conclusions in this article apply mainly to the middle 62% of jobs in the U.S. economy in terms of complexity. [...] This category includes skilled blue collar jobs and mid-level white collar jobs, such as upper level clerical and lower level administrative jobs."

The article says that the most common measure of employee ability in general, and presumably for the articles used in this meta-study, was the amount of money each employee earned. Presumably then most of these employees were doing routinized or semi-routinized labor that would lend itself to piecewise compensation. The above quote seems to be consistent with this interpretation. They are also only looking at employees of huge corporations, where each person is one of dozens or hundreds of others doing more or less the same thing.

So is this meta-study relevant to hiring programmers? Yes and no. Probably the measures that were found to have more validity are still going to have more validity than the ones that were found to have less validity. But at the same time using only these tests would be too simplistic; they were designed to predict which factory workers were likely to steal from the company or slack off. And while these are still important factors to consider, the challenges of a modern startup go way above and beyond this.

Essentially this research was designed mainly for situations where you're trying to scale up a large industrial process where you can make money by arbitraging the difference between the output of the average employee and the amount it costs to pay them. The closer you get toward environments where it's essential that each person contribute things that are unique and novel, the less it makes sense to rely on these sorts of hiring tools.

In short, I would say that the above research neither supports nor disconfirms the advice of the original blog post. Of course you could make the case (and maybe tokenadult believes this?) that employers should make hiring decisions mainly by using a series of multiple choice tests that have been empirically validated, but that's an entirely different argument.

Link formatting suggestion: I found the sentences broken by line breaks for links difficult to read (and it discouraged me from starting, because it looked like jumbled nonsense when I skimmed). Instead of a separate paragraph, just putting links in parentheses seems to work well; or even just as-is, because the auto-underlining highlights them.

But it would be helpful to have a line break to separate your cover letter from the FAQ itself. Something like:


[FAQ goes here]

> a general intelligence test used in hiring that could have a "disparate impact" on applicants of some protected classes must "bear a demonstrable relationship to successful performance of the jobs for which it was used."

This part has been revised in practical use all over the country in the last 10 years.

If a test shows group-X scoring on average lower than group-Y, this in itself now proves that the test is biased against them (in a racist way). There is no need to link the test's material to performance of a job. That part is irrelevant.


> EXECUTIVE SUMMARY: If you are hiring for any kind of job in the United States, prefer a work-sample test as your hiring procedure.

Hence if you are going that direction, you should also consider the possible lawsuits that would happen if your test shows any type of racial differentiation in the grade (for example due to environmental upbringing or cultural values of the testee), even if your test is 100% neutral to race and 100% spot on for job performance.

The linked article talks about a government agency (NYC Fire Department) who imposed a written exam for fire fighters; the judge ruled that the exam was discriminatory in results and was not shown (could not be shown) to be related to job performance. That's what made it illegal under Title VII of the Civil Rights Act.

You don't have to worry about this if you're a private California software company assigning work-sample tests that are "100% spot on for job performance." Job performance is not linked to race.

(If you think that job performance at a software company is linked to race, I recommend that you keep your opinion to yourself. Maybe you can use it to your private advantage! ... or maybe you have racist assumptions.)

> The linked article talks about a government agency (NYC Fire Department) who imposed a written exam for fire fighters...

Multiple choice question test: A, B, C, D. Not a written test. The word "imposed" is also a bit harsh. It's a test for fireman. Fireman that would be saving my ass in a fire.

> the judge ruled that the exam was discriminatory in results and was not shown (could not be shown) to be related to job performance.

The city is trying to remove the judge from the case and for his decision to be reversed.

You can also view the test for yourself (http://documents.nytimes.com/new-york-city-firefighter-exami...) and find out quickly it has everything to do with the duties of a fireman.

> If you think that job performance at a software company is linked to race, I recommend that you keep your opinion to yourself. Maybe you can use it to your private advantage! ... or maybe you have racist assumptions.

I don't think that. And I shouldn't have to defend myself from being called a racist just because I've entered a discussion that has different races involved (and am white, well, as white as a born-Russian gets). You should also concider how much damage throwing that keyword around can do.

My point was that it's no longer necessary to link the testing material to job performance. But only to simply show that test scores are different between the races. And then to be politically correct.

This has been the trend we've seen in the last 10 years with these types of lawsuits.

There are parts of this country that not only have socio-economic differences between the races that impact the abilities of the individuals, but in some cases have cultures that downright embrace ignorance. If you start testing people for any job that requires a slightly above average ability in those parts, you will get drastically different results in the grade average of the races. This should not be used against the employer.

If the test is correlated to job performance better than other options that do not have disparate impact, it is allowed under the law. FDNY was unable to prove that the test was correlated to job performance (because they didn't ever make that correlation, the test was a cutoff to be considered to be on the force in the first place), which was their undoing.

If you are a small company no one is ever going to get a statistically valid sample size that could demonstrate any bias. They can only discover that data if it were available. If they do a work-performance test on a computer and the results are not kept, and racial/demographic data is not kept about each of the applications and their performance, how can this ever come up? These sorts of concerns really apply mostly to government jobs and large corporations.

Outstanding comment. Especially since you wrote it in 30 minutes.

Very interesting that the best tests still have a low validity.

It's a dupe of a dupe, but worth rereading.


I'm sorry, but you've been rejected from my soon-to-be-founded startup company, because I only accept people who comment in 29 minutes or less. Taking a lot of time to comment could slow down meetings to a crawl, you see.

Also, unknown to you, I only accept people who write their comments in the form of a koan and wear red ties on interview day.


Many thanks to you and the others for putting this information together.

For those that can't see the post, try this - it's a cached version from Instapaper: http://www.instapaper.com/text?u=http%3A%2F%2Frefer.ly%2Fblo...

And we're sorry about the downtime on the blog! We're trying to fix it as we speak and it kind of caught us off guard, because the blog's handled being on the front page of HN all through the summer without a hiccup.

Could always try a little CloudFlare to handle the load.

I think a disclaimer might be appropriate here ;) Not that I mind at all; CloudFlare is awesome.

That is great advice on how to hire mindreaders. While the first idea (explaining something concisely) is defensible, the second (testing if people will 'stay on topic' when deliberately asked about something else) is just crazy.

I put a piece of paper on the desk in front of them. It has the number "3" with a big red X through it. Then I hold a baseball bat in a threatening position and tell them to give me an integer between 1 and 10.

This technique works wonders, as I'm able to filter out the 90% of candidates who are losers.

Spoiler: the right answer is 8.

Saw this in an article about Google from last year: http://online.wsj.com/article/SB1000142405270230491110457644...

About Sergey Brin: "I'm going to give you five minutes," he told me. "When I come back, I want you to explain to me something complicated that I don't already know." He then rolled out of the room toward the snack area. I looked at Cindy. "He's very curious about everything," she told me. "You can talk about a hobby, something technical, whatever you want. Just make sure it's something you really understand well."

Really like this. Covers a lot of bases in a single question, such as curiosity, depth, interpersonal skills, etc.

I hate, hate, HATE gimmicky interview questions. At my job I am asked frequently to be on interview panels for my own department and sometimes other departments. It seems like every manager running the interviews throw out these trick questions at some point or another and I just cringe.

There is no magic recipe for interviews. Ask about the person, ask about their experience, see work examples if appropriate and ask some questions to gauge knowledge level for the position being applied for. Anything more and you are just going to second guess yourself out of a good candidate.

This submission has only 14 points at this time, and the server is already a smoking crater.

Lesson: Ensure your infrastructure can handle the traffic before you submit links to social sites.

The high traffic to the blog post has brought their entire site down.

It's always a good idea to host the blog separately from the site - best is to use a managed solution (tumblr, wordpress.com, etc..)

It might not have been the author submitting the site

True, though in this case it was.

So uh, what is the question?

How do you know how much traffic you will get?

I have no idea how many people visit HN and how many click on any given link in what space of time.

Maybe PG or someone can give some guidance?

If you can't handle a couple of 1000 hits in a short time period... does wordpress still default to not having any caching solutions at all out of the box?

I saw a load of about 200-250 simultaneous visitors when one of my sites got posted from ycombinator to the reddit. After 12 hours it tapered off.

There's no excuse for failing under that kind of load serving what is essentially a small, static text document.

You can assess almost nothing that would distinguish one qualified candidate from another to determine who is better spending five minutes with a person. The fact that you see the faults you predicted when you were overruled on hiring decisions is a confirmation bias, not a scientific study of any kind.

Job interviews are a terrible method of hiring good long term people, just a necessary evil to weed out the moronic or insane. The concentration has to be long term on how the person does on the job, the willingness to work hard to retain good people and get rid of ones who aren't working out.

People who are involuntarily committed are observed for more than an hour, because it's known that an insane person can hold it together and appear normal for longer than that period of time before they start talking to people who aren't there.

I couldn't be more sick of posts with "that one interview question" and people who think they are clairvoyant "five minute judges" of character.

Very good question. This could not only apply to programmers, but anyone involved in communicating complex issues (medical personnel, engineers, etc).

On a side note, I do not read that many articles about the effectiveness of hiring. It certainly deserves more attention, because the good people in the right places is so important.

Start-up idea: Provide companies with interview questions for specific jobs, and then measure employee success/failure and use this to improve the process.

"At the beginning of the 5 minutes you shouldn’t assume anything about what I know"

This part of the question would really throw me off. If I want to explain wood working, and I can't assume you know what wood is, we are in trouble.

I think it is meant to say don't assume there is any domain specific knowledge known ahead of time. That would make more sense to me.

How about a meta-answer?

"I am really passionate about an interview question, which I like to call the most revealing job interview question.

It’s without a doubt my favorite interview question, because it only take 5 minutes and tells me a remarkable amount about candidates. Even though it’s not a technical question per se, I still give it to every programmer I interview.


For senior positions, I will ask a question early in the 5 minutes that is a complete tangent and has little to do with their goal. A star candidate will politely refuse to go down this rat hole and insist that we stay on topic. This seems unfair since an they’re in an interview and just doing what they’re being asked. In reality though, the very same thing happens often in real work. Even mangers do not innately know what is most important about a topic, and it’s key to have confident people on the team that add focus to conversations."

For senior positions, I will ask a question early in the 5 minutes that is a complete tangent and has little to do with their goal. A star candidate will politely refuse to go down this rat hole and insist that we stay on topic. This seems unfair since an they’re in an interview and just doing what they’re being asked.

Got that right. Trick questions are always unfair (and mildly insulting, and just a plain waste of time) in interviews, just like they are in real life.

"Star interviewers", on the other hand, know that there's no reason to ask candidates to jump through artificial hoops like these.

While interesting and thoughtful, I dislike trick interview questions where you tell the interviewer one thing, but look for another. The first problem is that someone who knows what you're doing, had read this article, for instance, has a huge advantage. The other problem is that it during an interview, I try to get people to relax so that I can get a sense of what they're really like. When they're on their guard of trick questions, it creates the opposite environment.

I think the "trick" elements of it may have been over emphasized by my blog relative to how I really do this question. Ultimately, the core of the question is hard enough, and does plenty to figure out who's a really good communicator. Just explaining something in essential form is actually quite hard.

Can somebody just post the question? Server's aren't responding.

I want you to explain something to me. Pick any topic you want: a hobby you have, a book you’ve read, a project you worked on–anything. You’ll have just 5 minutes to explain it. At the beginning of the 5 minutes you shouldn’t assume anything about what I know, and at the end I should understand whatever is most important this topic. During the 5 minutes, I might ask you some questions, and you can ask me questions. Take as much time as you want to think it through, and let me know when you want to start.

The question I ask at the beginning is "tell me about something you are proud of". This helps sets them at ease, gets them to brag/market themselves and is positive.

Later on I pick something prominent on the CV/resume and ask them to explain it in detail on the whiteboard. I try to pick something with multiple components communicating over time (web browsers/mobile clients talking to servers is good). That requires sequencing, boxes, and arrows. The answer also helps set expectations on other items on the CV/resume - if they can't explain something they claim to know well then the other items are likely an exaggeration too.

I never penalize answers of "I don't know" to questions about parts, but am astonished at how few candidates will say that. For example they'll say "there is a POST". I'll ask what a POST is. They'll mumble something incomprehensible about HTTP. So I'll ask what a POST is, again. They'll mumble something about GET, and I'll give up. There is no problem with not knowing - Google/Wikipedia/Stackoverflow will address almost all things - but it is a huge red flag not understanding something, being unable to explain it, and being unprepared to say so.

Why can't you find out the same information about the persion by just engaging in normal conversation, asking them about their interests, and asking reasonable follow up questions?

Presenting it as some kind of weird test that makes the interviewee feel awkward and suspicious is no way to conduct an interview. It says more about how bad the interviewer is.

They avoid a normal conversation because then the interviewer would not be able to be achieve a master smug rating. You need to be psychic and 'get' what direction or type of response that they expect.

I definitely do this. I think these clues come across throughout the entire interview.

The post is apparently a marketing effort. The interview question is pretty old. If it is that effective as claimed, it would have been known and applied widely. (Then, candidates will prepare for the question and it is not revealing at all.)

Also, claiming any interview question as <bold> MOST </bold> revealing is simply simple-minded.

>>> Here’s how I set up the question:

>>> I want you to explain something to me. Pick any topic you want: a hobby you have, a book you’ve read, a project you worked on–anything. You’ll have just 5 minutes to explain it.

I am an experienced technical guy. In case of technical interview if somebody starts away with that kind of question; i would take that in a negative way. I hate it when interviewers instead of being focused on their requirements focus on unnecessary things. As a job seeker i would like to be felt that i am required for the position; and that am not just a guy seeking money or a change in job. I would like to have the interviewer ask me questions for the job-position that i've applied; such that i feel motivated to continue; and know that the interviewer is serious about the position; and is just not filling up vacant company position.

I've interviewed at many places, and received many offers. What ever happened to no BS, sit down and have an honest conversation. I'm done with interview questions.

People hiring fret so much about tricking candidates into revealing certain qualities. The candidate will give you the answer they think you want.

This is one of my favorite interview questions as well! I originally got the idea from an autobiography of an early Google employee; apparently this was one of Sergey's favorite questions.

Definitely helps you see how effective people are at organizing their thinking and communicating it effectively.

I would have thought that the author would have bothered to proof read the question.

It's not given in written form - it's a friendly oral conversation.

I think this post has a lot of interesting points, but in general I find asking interviewees questions that are not related to their job a little weird because no you are basing your judgement on things unrelated to the actual position.

However, if we changed this question to "in 5 mins. please explain the most important partt of X" where X is some relatively commonly understood computer science topic, I think it would be a much better interview question. And if you want you can still look for the traits empathy, goal directed, etc..

> I will ask a question early in the 5 minutes that is a complete tangent and has little to do with their goal. A star candidate will politely refuse to go down this rat hole and insist that we stay on topic.

These types of "trick" questions don't allude to anything. A star candidate also wants to respect their interviewer and refusing to answer a question can be seen as disrespectful.

Granted, the characteristic you're trying to surface is a fantastic one (saying no) - but this is not a surefire way of discovering it.

It is a terrible way of discovering it.

It's the same as if they asked you a php question. You answer it, and then they say 'wrong!!!! the right answer is php sucks, in ruby I do it like so:...'

I refer.ly they are looking for a senior software engineer with good knowledge of php and mysql. So perhaps the title should be "The Most Revealing Job Interview Question for Finding a Good PHP Developer".

A very conservative approach, in this landscape every single decision must be attached to a clear goal, there is no room for experimentation, you should follow a direct goal Explain to your team how can get they solve the problems for their clients and describe the path for this goal.

Based on the numbers provided in the post, it sounds like the best case scenario is:

o). 41 people got hired in total after being asked this question. o). 4 of those were hired despite answering it badly. o). Those 4 people did not do well. (these were hires where the manager was specifically overruled in hiring them) o). The other 37 did well. (these were hires where the manager was not overruled)

Ie. an interesting, thought provoking post, but tough to draw any definitive conclusions..

I remember a similar test from one of the books by Lister & DeMarco. They also mentioned one caveat not present in the linked article: they advice not to let the candidate choose the topic but instead let them prepare a presentation on a pre-chosen one. The rationale for this is that you might see passion and quality that are only attached to topics the candidate is passionate about if the choice of the topic is with the candidate.

I had to do this in an interview for a software project manager position. I presented on how GFP-tagging of proteins works in biochemistry research, to an audience of glassy eyed HR reps.

I was hired, but the point is that you can't allow the presenter to take something too technical, otherwise the audience won't understand the jargon.

Computers don't have empathy. Sometimes a cold and rational personality is what you need when you have to deal with compiler errors and stack traces all day.

Slightly tangential.

I've been running an experiment of my own. As part of my work, I need to hire freelancers for dev, design and so on. It's not specific to the tech field, I also hire virtual assistants as well.

I've been working with devs on and off for about 10 years and have my fair share of experiences.

I don't interview people that I hire/sub-contract to, I just chat to them. Maybe there are people out there that do interview, but I find it a bit strange, so asking the "5 min" question as per the blog post would be a little weird.

But I've been doing some experimenting for quite some time. It's really important that the people that i choose to sub-contract to work well with me as part of a team.

When put out an ad for a freelancer of a particular kind, I deliberately say something that paints me as a potentially difficult client. I tend not to let on how much I know about the field that i am looking to hire in either.

The results are always amazing. The ones that contact me that don't make even the slightest mention of the possibility of me being difficult, or find a way to laugh about it, are the ones that i choose to do business with first.

These people are so intent on focusing on the positives that they don't even notice my poor behaviour. It's that enthusiastic attitude that makes them a really good team player.

Of course, after i establish the business relationship with them, i do my level best not to be a difficult client for them.

Personally, i always feel that the relationship you have is far more important than the skill set, and the rates being charged.

I've tried this experiment a few times - I call it my freelance filter.

One example is a project that a freelancer worked on for me when i first tried this filter. His skill set was a bit worrying to me. I had spoken to others that were more experienced, but i loved his attitude and he passed my filter test with flying colours.

Anyway, i hired him and he far exceeded my expectations in every way. Was very responsive, communicated really well, exceeded my expectations on the project and over-delivered voluntarily and gave plenty of his own creative input without being detrimental to the project.

Anyway - just thought i'd share. It might rile a few people up, but maybe one day someone will benefit from using this process.

Or you are simply weeding out the top class of freelancers before they even contact you because they have enough options that dealing with a potentially aggravating client isn't worth a response.

I do agree that, of those who remain, filtering out those who fixate on negative aspects of the relationship is a good idea. Those people will often look for negative things, even if none are there, making them painful to work with.

That's also deliberate by me as well. If they have enough options and they're busy enough then we shouldn't be working together because they have a fair amount on their plate.

It's not a perfect filter. You are indeed correct. I would be wary about a client that demonstrates certain traits as well.

I do not give any “uh huh” or “I see” kind of interjections that underlie most conversations.

And you want to use this method to gauge a candidates communication skills? Human communication is a very complicated and error prone process. If you're going to cut out all the vital clues, how you can expect it not to fail horribly? Feedback from both sides is essential.

No. At first, he doesn't give any indications to check if the candidate recognize this lack of understanding.

As you said it very well:

  If you're going to cut out all the vital clues, how you can expect it not to fail horribly? Feedback from both sides is essential.
If your audience doesn't acknowledge your basic explanations, it's not worth going deeper in the subject. I.e. If you get no clue, go get them!

He states he gives a deer in the headlights look. Assuming he performs it well this is a very clear communication of: "I have no idea what you're talking about"

So by not offering the routine and quick forms of 'yes I understand', a good communicator will stop to see where the holdup is, a bad one will march on without noticing there was an issue.

By cutting out all of the vital clues, the interviewer is making sure that the candidate is even remotely looking for them. Too many clients will smile and nod when they don't understand something. That's far less of a telling sign than staring blankly.

When explaining things, I somewhat worry that I'm going to come off like an arrogant prick when I look someone in the eye and ask "Does that make sense?" If you don't, though, you run the risk of people not opening the floodgate of questions they have -- or, worse, you run the risk of assuming that they actually understand and that everything is golden.

I love interviewers' tips, upvoted. However, it's not clear to me how Kevin is able to "ask a question early in the 5 minutes that is a complete tangent and has little to do with their goal" to see if they "say no". As much as you want to test the candidate's confidence, you have to ask a relevant question. Maybe an example could help?

Here's a good example... one candidate chose to explain how residential firefighting works. They got into explaining why water is really important. I asked them about halon and they indulged a little bit. Then I asked them to explain how halon works. And so on...

If they haven't shut me down by the 3rd question, it's a sign they're never going to, and I stop distracting them.

For junior candidates, I usually don't even bother with this, because I am not going to stop myself from hiring just because they fail this question. So it's usually better to see if they can do well at just the core question.

> –anything

Let me show you my collection of cat whiskers, it's right there in my tinfoil hat.

That would be a very useful reply. It would effectively communicate to me whether you would make a good hire.

Are you running a cat whiskers collectors exchange? We definitely should talk.

Oh, this is indeed an awesome question. I would've appreciated to be asked it if I were interviewing somewhere. There's so much I can tell about bacon :)

Seriously though, it's a very clever question. Thanks for sharing.

What was the question? The site seems to be down and Google doesn't seem to have a cached version yet.

Paraphrased: Ask the applicant to explain any topic for 5 minutes to the one interviewing. Then the interviewer will draw a blank face. Talented applicants will ask the interviewer if he understands, less talented applicants will just continue their story.

(paraphrasing) Choose a topic and explain it thoroughly to me in 5 minutes. Impress me with your clarity and conciseness. Secret bonus challenges: Respond appropriately to my blank stares. Resist my tangential distractions.

"Pick a subject that you like and know well. You now have 5 minutes to explain it to me and make me understand what's the most important thing about it is. Go."

Along these lines, the CIA requires all applicants for foreign office positions to fly to Washington and deliver a 5-minute briefing on a topic of national security as part of their interview process.

So question about this question: do you think this can be trained (and if so, would that training help with job performance) or it's just an inherent characteristic?

It can definitely be trained and practiced, so quite clearly it is going to skew towards those that read blog posts about hiring.

The thing is if you're good at this, it translates into real work performance. So I almost don't care if people have "cheated" and studied up on the question. None of the people I've hired suddenly stopped communicating well on the job after doing well on this question.

I think this is the part where you're doing some magical thinking backed up by anecdotes. Have you done any actual experimental work on those who have failed the question but that you've hired anyways? Have you then been able to objectively measure how well they communicate? Your sample size seems pretty small (a couple hundred) so my guess would be no. I frequently see this kind of thinking about interview questions: "If somebody fails this problem this way, then they'll perform poorly on the job in the following way." Unless you actually have performed a study on this kind of thing, then you're probably just guessing when you say those kinds of things, and you're showing a lot of not particularly rigorous thinking about the relationship between the interviewing process and on the job performance.

It's definitely a small sample size, but I have more data on this than any other techniques I've seen out there.

I've been overruled once after no hiring a candidate. Low and behold the same person ended up nearly getting fired 9 months later for the very same issues that came up from this question. They struggled to answer even the simplest questions with one sentence responses.

So, that's a sample size of 1. Not quite what we would call scientifically rigorous ;). I'm not saying it's not a useful question. I'm just saying, you jump to a whole lot of conclusions that are clearly not based on evidence in your hiring process. That's fine, just be aware that your hiring process is not doing what you're thinking or asserting it's doing.

Split the pile of application in two halves. Throw one of the halves in the trashcan. Hiring people with bad luck isn't good for business.

While often given as a joke, this is effectively what many of these "best interview question" posts really are:

Find any random old way to save time and effort in the interviewing process, then come up with some clever-sounding rationalization.

From the article that has ceased to be:


We have been doing a lot of interviewing at Referly lately, and my team asked me to share an interview question we get the most mileage out of. I’ve been doing this question for years and now have seen over two hundred different answers now. It’s without a doubt my favorite interview question, because it only take 5 minutes and it tells me a remarkable amount about candidates. Even though it’s not a technical question per se, I still give it to every programmer I interview.

Setting up the interview question

Here’s how I set up the question:

I want you to explain something to me. Pick any topic you want: a hobby you have, a book you’ve read, a project you worked on–anything. You’ll have just 5 minutes to explain it. At the beginning of the 5 minutes you shouldn’t assume anything about what I know, and at the end I should understand whatever is most important this topic. During the 5 minutes, I might ask you some questions, and you can ask me questions. Take as much time as you want to think it through, and let me know when you want to start.

When I give this, I usually emphasize each of these points multiple times, with a real stress on their goal: have me understand what’s most important about the topic.


As they start explaining, I make sure to have the most vacant look on my face possible. I do not give any “uh huh” or “I see” kind of interjections that underlie most conversations. A star candidate will pick up on this and ask if I understand so far. On the job, these star candidates also are the same kind of people that empathize with customers and think about it in all the work they do once we hire them. Conversely, weaker candidates think that presentation and communication are one in the same, and loose sight of their audience. They end up being the hardest developers to work with just to understand how they’re solving a problem, much less have a constructive argument with them.

Explaining by analogy is a shortcut some of the best candidates use. One example I heard while someone was teaching me the basics of poker was to take advantage of the fact I had played backgammon even though I hadn’t played poker. He talked about how in backgammon all the pieces on the board are exposed information that both players can see, but in poker you have hidden information. These type of explanations go a long way towards quickly communicating an idea with all kinds of implications very succinctly.

Goal directed and organized

It is amazing how many candidates will not premeditate before diving into this interview question. Once the trigger happy type candidates get going, they don’t have any kind of bulleted list or outline in their head of what they hope to get across. What’s most incredible about this is how accurately it predicts disorganized and non-goal directed behavior on the job. I’ve been over ruled a few times by my manager on a hiring decision, and question was a harbinger of things to come. Conversely, the people that think it through and have a few crystal clear points are amongst the best people I’ve worked with. They are not just easy to communicate with, but get results in their work.

Leaders have the guts to say no

For senior positions, I will ask a question early in the 5 minutes that is a complete tangent and has little to do with their goal. A star candidate will politely refuse to go down this rat hole and insist that we stay on topic. This seems unfair since an they’re in an interview and just doing what they’re being asked. In reality though, the very same thing happens often in real work. Even mangers do not innately know what is most important about a topic, and it’s key to have confident people on the team that add focus to conversations.

Stacking up

Usually only 1 or 2 out of every 10 candidates will do well on all these points. That has held true after giving this interview question over two hundred times.

I take a risk sharing this, because this question has been an amazing tool in picking apart the best talent from rest. I ended up deciding this was worth sharing because after years of telling people exactly what I am looking for in the set up, weaker candidates still can’t help but get tripped up.

Want to experience it first hand? We have open positions right now :)

Wasn't it originally Bezos who requested interviewees to tell, elaborately, about something he doesn't know?

Sooooo. Why did you just give away one of the best questions to ask at an interview?

I like it. It's pretty close to my favorite one: "What's your favorite algorithm?"

Totally stealing this.

For those who can't see the page - the answer is 42.

refer.ly just dropped the ball on this one.

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