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Ask Slashdot: Are Timed Coding Tests Valuable? 776

First time accepted submitter xkrebstarx writes "A buddy of mine recently applied to a large tech company. Before setting up a phone interview with him, the unnamed company issued a timed coding test to gauge his coding prowess. He was allotted 45 minutes to complete an undergraduate level coding assignment. I would like to ask the Slashdotters of the world if they find value in these speed-programming tests. Does coding quickly really indicate a better programmer? A better employee?"
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Ask Slashdot: Are Timed Coding Tests Valuable?

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  • I dunno... (Score:5, Insightful)

    by Joce640k ( 829181 ) on Thursday January 10, 2013 @09:03AM (#42544543) Homepage

    I dunno...but it will weed out the pretenders/bullshitters.

    •     I guess it would prune out those who would take 2 hours to print "Hello World".

      • Re:I dunno... (Score:5, Insightful)

        by hackula ( 2596247 ) on Thursday January 10, 2013 @09:32AM (#42544733)
        I never believed the whole "95% of interviewees fail the FizzBuzz test" until I started interviewing candidates. People with 15 years of "experience" on their resume would regularly fail or give up. I also encouraged googling, including just searching for the exact problem, and I encouraged questions and told them that both behaviors were seen as a good thing. IDK how someone could possibly get through a CS program and still fail this test, but it happened regularly.
        • Re: (Score:3, Funny)

          by Anonymous Coward

          wth is a fizzbuzz test?

          • Re:I dunno... (Score:5, Informative)

            by beelsebob ( 529313 ) on Thursday January 10, 2013 @09:38AM (#42544793)

            Well, you just failed for not googling...

            But, print all the numbers from 1 to 100, except rather than printing multiples of 3, print fizz, rather than printing multiples of 5, print buzz, and for multiples of both, print fizzbuzz.

            • Re:I dunno... (Score:4, Insightful)

              by Anonymous Coward on Thursday January 10, 2013 @10:11AM (#42545115)

              -- pseudo-code
              for i in 1 to 100 loop
                    if mod(i,15) == 0 then print 'fizzbuzz' ;
                    elsif mod(i,5) == 0 then print 'buzz';
                    elsif mod(i,3) == 0 then print 'fizz';
                            print i;
              end loop

              -- 4 minutes to write pseudo-code, maybe not elegant, but not googling
              -- Depending on the language, I'd have to to look up the print, loop, and modulus syntax

            • Re:I dunno... (Score:5, Insightful)

              by Anonymous Coward on Thursday January 10, 2013 @11:28AM (#42546097)

              I don't understand why employers don't just ask to see some code the developer has already written. Some people (nerds) don't do well in social situations and it takes a few days to get into the swing of things.

              I really don't get the "write a merge sort" routine. When was the last time someone did this IRL? At least people can use google, etc. When I was outta college, we had to do this crap on a whiteboard with 5 guys staring at the back of your head with no references. Talk about nerve racking.

              I would think the best possible thing to do would be to ask the candidate to write something before the interview and give them a few days. That way they are in their comfortable environment and can do their best work, proofread, comment properly, debug properly, optimize properly, etc. That's what you're really after, not someone who can write buggy ass, un-commented, un-optimized code really fast.

              • Re:I dunno... (Score:5, Insightful)

                by fzammett ( 255288 ) on Thursday January 10, 2013 @12:20PM (#42546837) Homepage

                Wish I had the mod points, but this is spot on.

                I've frankly never been particularly good solving these "simple" algorithmic problems on the spot either, even with my 20+ years of experience in the field, even with being a published tech author, even with being very highly regarded by all I've ever worked with. So, although I haven't had the need to interview for a job in quite a few years, I'm sure I wouldn't do any better than average if these sorts of things were thrown at me.

                But, compare the code I write for a living with the code most others do and there's no question which one of us you'd want to hire.

                I think this is true of a lot of good developers... there's MUCH more to this job than being able to solve a specific single programming task because all of us that are worth hiring can do that, given enough research and time... sure, I agree, it's nice if you can throw algorithm X, Y or Z up on a whiteboard from memory, that'll make you marginally faster than me... but speed, while not irrelevant, is FAR from the most important characteristic of a good developer. Code that is clean, elegant, logical, as simple as possible and maintainable five years down the road are FAR, FAR, FAR more important, and you're NOT going to gauge those things with a fizzbuzz-type test (I do A LOT of interviews now, believe me, I know this from experience).

                • Re:I dunno... (Score:4, Informative)

                  by dward90 ( 1813520 ) on Thursday January 10, 2013 @02:33PM (#42548687)

                  While you're absolutely correct that a fizzbuzz test is not a good way to determine if you *want* to hire someone, I think you're missing the point of these kind of exercises. It's purpose is to weed out candidates who are a complete waste of time. Trivially simple programming tests don't tell you if a person is a good developer. A passed test means basically nothing. However, a failed test means that to spend any time interviewing that candidate is a complete waste.

                  Note that I'm talking about really simple stuff, with no real time limit and not caring about bullshit syntax (You forgot a semi-colon! Go home!). I would never expect an experienced developer to code out complex sorting or search algorithms from memory. Those tests, for sure, don't tell you anything.

        • Re:I dunno... (Score:5, Interesting)

          by Cryacin ( 657549 ) on Thursday January 10, 2013 @09:37AM (#42544779)
          These tests are vital when interviewing. We recently put out an ad for a senior programmer, and got about 100 or so responses. After 25 responses hit the circular filing cabinet, as they were obvious resume spam with no cover letters, we declined around a further 50. Of the remainder, we asked a simple question. In JavaScript, without using the reverse() method, reverse an array of numbers containing 1,2,3,4,5 in the most efficient way possible.

          We got 5 responses back, which we interviewed. The other 20 were out. These tests are meant to weed out the crap that would waste our time, and honestly, the 5 guys that responded, responded in under 5 minutes.
          • by arth1 ( 260657 )

            To be fair, there are a lot of senior programmers who don't speak javascript. They may have experience in it to the point of setting up the algorithms that the regular programmers implement, or assisting with eyeballing for glaring errors, but may not be javascript programmers themselves.

            An efficient solution would, depending on the language, be to either change the pointers of the array, or create a new index to replace the existing one, and thus avoid copying each element, but I can fully understand seni

          • by IICV ( 652597 )

            Honestly, you didn't even need the "without using the reverse() method" stipulation.

          • Re:I dunno... (Score:4, Insightful)

            by mcmonkey ( 96054 ) on Thursday January 10, 2013 @10:38AM (#42545447) Homepage

            In JavaScript, without using the reverse() method, reverse an array of numbers containing 1,2,3,4,5 in the most efficient way possible.

            Semi-off topic question: really? I mean, are we (programming job seekers) as a group that dumb?

            I recently went through searching for a programming job after 5 years in a position that mainly dealt with configuring off-the-shelf apps. Every single interview at some point had a question that required reversing an array without using Reverse(). (Only about half mentioned efficiency.)

            I'm big into puzzles and logic games, and as long as I can use pseudocode and not stress syntax, technical interviews are truly fun. I enjoy coming up with algorithms to solve interesting problems. But reversing an array is not an interesting problem; it's trivial. It got the point where I felt like I should walk in to an interview, introduce myself to everyone in the room, and go right for the white board and put up an array-reversing function, just to get it out of the way.

            That a significant number of applicants for a programming position couldn't (or wouldn't) solve this quickly is sad commentary. (It's even worse if you consider it's likely yours would not be the first position these folks have applied for. Based on my experience, they would have been asked the same question previously, and not only couldn't come up with a solution, but also didn't think, maybe I should figure this out before I send out any more resumes.)

        • by serviscope_minor ( 664417 ) on Thursday January 10, 2013 @10:10AM (#42545103) Journal

          I never believed the whole "95% of interviewees fail the FizzBuzz test" until I started interviewing candidates.

          Well, I've never interviewed job candidates and I have a hard job believing this. It's not that I think you're lying (I don't), it's that I've never seen it for myself and my brain has a very hard job accepting that someone who does programming for their livlihood could not solve this in their sleep.

          It doesn't matter that it's true, it's just really REALLY hard to imagine. And I don't WANT to believe it.

          Anyway, here's my entry.


          #Advance the number counter



          #Advance the Fizz counter

          #Clear the hold space

          #Divisibility by 3 /c/{

          #Divisibility by 5 /[05]$/{

          x /^$/g
          x /100/!bmainloop

          Silly slashdot. Why do you keep reformatting my code and why do you make me type junk here just to get my post accepted? Blah blah blah blah blah blah and you don't like too much repition wither this makes it very hard to paste code into the forum now please let this post in please pretty please with a cherry on top and sprinkles and is that even your bucket in the first place?

        • by Anonymous Coward on Thursday January 10, 2013 @10:20AM (#42545223)
          That's easy; I'm a fast typer!

          #include <stdio.h>
          int main()
          puts("1"); puts("2"); puts("fizz"); puts("4"); puts("buzz"); puts("fizz");
          puts("7"); puts("8"); puts("fizz"); puts("buzz"); puts("11"); puts("fizz");
          puts("13"); puts("14"); puts("fizzbuzz"); puts("16"); puts("17"); puts("fizz");
          puts("19"); puts("buzz"); puts("fizz"); puts("22"); puts("23"); puts("fizz");
          puts("buzz"); puts("26"); puts("fizz"); puts("28"); puts("29"); puts("fizzbuzz");
          puts("31"); puts("32"); puts("fizz"); puts("34"); puts("buzz"); puts("fizz");
          puts("37"); puts("38"); puts("fizz"); puts("buzz"); puts("41"); puts("fizz");
          puts("43"); puts("44"); puts("fizzbuzz"); puts("46"); puts("47"); puts("fizz");
          puts("49"); puts("buzz"); puts("fizz"); puts("52"); puts("53"); puts("fizz");
          puts("buzz"); puts("56"); puts("fizz"); puts("58"); puts("59"); puts("fizzbuzz");
          puts("61"); puts("62"); puts("fizz"); puts("64"); puts("buzz"); puts("fizz");
          puts("67"); puts("68"); puts("fizz"); puts("buzz"); puts("71"); puts("fizz");
          puts("73"); puts("74"); puts("fizzbuzz"); puts("76"); puts("77");
          puts("fizz"); puts("79"); puts("buzz"); puts("fizz"); puts("82"); puts("83");
          puts("fizz"); puts("buzz"); puts("86"); puts("fizz"); puts("88"); puts("89");
          puts("fizzbuzz"); puts("91"); puts("92"); puts("fizz"); puts("94");
          puts("buzz"); puts("fizz"); puts("97"); puts("98"); puts("fizz"); puts("buzz");
          return 0;

        • Re:I dunno... (Score:5, Interesting)

          by FictionPimp ( 712802 ) on Thursday January 10, 2013 @11:32AM (#42546151) Homepage

          Yes and no.

          I have taken programming tests for jobs. I tend to do really well and have gotten quite a few jobs and job offers from my tests. I excel at tests that give me a few days to complete some minor 'real world' type project. These jobs typically had more knowledgable staff and they used my 'test answer' application as a launching point for a discussion on my ability. They did this by challenging my design decisions, asking questions about areas in the code to get my insight, and asking me how I would improve the program given more time, or improve the test.

          I have also bombed tests that were timed asking programming questions. Many of these tests asked for simple things (print out a multiplication table to look exactly like this example) and I simply brain farted because I don't typically write applications that need console formatted output. I end up looking like a idiot to the test givers. I found no value in these tests asking me to write a function that factors, or write a loop that prints out hello 10 times. Interviews after these tests tended (when they happened at all) to be lower quality and the employees seemed less knowledgable. There was much less meaningful discussion about my abilities, even when I 'aced' the test.

          When I do my job in real life, I have time to plan, research, and I can keep open documentation for reference. I don't need to memorize every obscure function in the language my job requires, instead I can pull up documentation on how to use that object, function, or method. Many tests I have taken do not allow for this and it has cost me a few job interviews. While you have stated you encourage googling, most tests I have taken have explicitly denied the ability to search. I'd much rather have a week to build a working application then 45 minutes to prove I know how to write boilerplate code and memorized a whole bunch of console formatting functions.

        • Re:I dunno... (Score:4, Insightful)

          by Ihlosi ( 895663 ) on Thursday January 10, 2013 @01:56PM (#42548147)
          People with 15 years of "experience" on their resume would regularly fail or give up.

          I'm curious ... can you elaborate on how exactly they fail?

          Do their attempts just have stupid bugs or is the whole approach wrong?

          I'd probably fail at "printing". Only writing code for devices without any human-targetted outputs does that to you. :P

      • Presumably the exercise is more complicated than "print Hello World".
    • Re:I dunno... (Score:5, Insightful)

      by beelsebob ( 529313 ) on Thursday January 10, 2013 @09:11AM (#42544593)

      The other thing it'll do is near guarantee that they get some bugs from all applicants, they'll then have something to discuss in the phone interview, and gage the applicant's responses and proposed fixes.

      • Re:I dunno... (Score:4, Interesting)

        by SJHillman ( 1966756 ) on Thursday January 10, 2013 @09:36AM (#42544767)

        Mod parent up

        I took a couple of programming classes in college and we had some timed tests. However, failing to get the desired results within the allotted time was only enough to knock off a partial letter grade (IE: go from a B+ to a B). The professors mostly wanted to see how you approached a problem, whether you commented your code, if any horrible coding practices jumped out, etc. In the follow-up, they would also want to know how you would fix any issues you came across if given more time.

        How much you got done was still somewhat important - there was a basic expectation that you would have some functionality working and other pieces at least partially completed. After all, if you have to spend 45 minutes looking up how to do a basic loop, then you're probably not experienced enough for anything beyond entry level (if that), so it helps weed out the people who are outright lying about skills.

    • Re: (Score:2, Insightful)

      by Anonymous Coward

      Exactly. I don't believe that a speed programming will always identify the "better" programmers or employees as the OP appears to be making a correlation between.

      I would suspect that the company is just trying to weed out those who actually have no experience, not those who are "better". It is just a method of screening which can be very effective when dealing with large numbers of applicants.

      • by deniable ( 76198 )
        It sounds like less of a speed comparison than an upper limit to stop people wasting both sides' time.
    • by Anrego ( 830717 ) *

      Pretty much this.

      Typically prior work is used for this purpose, but I could see this being valuable as a "you must be this competant before we will bother talking to you seriously" type test.

      Also without knowing the scale of the coding assignment, we can't know if 45 minutes is barely enough time or a very reasonable amount of time.

    • Re:I dunno... (Score:4, Insightful)

      by smpoole7 ( 1467717 ) on Thursday January 10, 2013 @10:19AM (#42545211) Homepage

      It's not only a great idea to weed out the wannabes, watch how they react when you challenge them.

      The ones whose eyes light up and are eager to prove themselves? That's your guy or your gal. :)

  • If asked for simple answer, here it is.
  • The answer is... (Score:2, Insightful)

    by oPless ( 63249 )

    Emphatically NO

  • Of course (Score:5, Insightful)

    by Bogtha ( 906264 ) on Thursday January 10, 2013 @09:07AM (#42544565)

    They are extremely valuable - they let you know which potential employers don't have a clue about programmer productivity / expertise.

    • Re:Of course (Score:5, Informative)

      by buddyglass ( 925859 ) on Thursday January 10, 2013 @10:02AM (#42545017)
      I took one of these during an interview. They put me in a room w/ a computer my IDE of choice and had me do a project. The general gist was to build a program that read instructions from a file, parsed them, carried them out, then output the result at the end. The instructions all had to do with string manipulation. After I finished, they brought my code up on a projector and had four or five developers do a sort of code review, asking me why I chose to do various things in certain ways. So, not only did they test whether I could finish the project successfully, they got to see whether I can speak intelligently about design decisions and handle constructive criticism from other developers. Seemed like an extremely valuable exercise.
  • I personally discard any company that tests undergraduate-level stuff.
    This kind of thing is completely irrelevant to the skills of a senior engineer.

    • by beelsebob ( 529313 ) on Thursday January 10, 2013 @09:12AM (#42544601)

      I personally discard any applicant that thinks like this, it means they can't actually think about algorithms, data structures, and how to design something well, and in doing so will produce sloppy assed code.

    • Re: (Score:3, Informative)

      by nedlohs ( 1335013 )

      You really think that would be for a senior engineer position?

      Unless it's an ungraduate assignment from a very specialized course it's going to be simple to do in less than 45 minutes. The only assignment I have done or set at an undergraduate level that wouldn't have been so was the "write a ray tracer" from a computer graphics course - and only because I don't remember the math off the top my head (it almost writes itself once you have that), I'd need to reread some stuff first.

      Is it going to "indicate a

      • by qwijibo ( 101731 )

        I use the programming exercise to determine if the person's computer skills match their claimed skills. From the resume and interview, I should have a good impression of what the person has done and could do. If I describe the problem to them and they say they can easily do it in 10-20 minutes, that's a good opportunity to nut up or shut up. The better they do, the more confidence I have in everything else they told me. If they claim lots of experience and are uncomfortable being put in front of a compu

      • by n7ytd ( 230708 )

        You really think that would be for a senior engineer position?

        Unless it's an ungraduate assignment from a very specialized course it's going to be simple to do in less than 45 minutes.

        But the fizzbuzz test isn't the only question to ask, and for anyone who's interviewing as a potential programmer, it should only take 5 minutes of interview time. The purpose is to avoid wasting anyone's time with the follow-up questions.

        Yes, the fizzbuzz test is trivial for a senior engineer, but it is still valuable because a large portion of "senior engineers" will still fail it. There is a difference between engineers who have mastered the trivial and moved on to bigger things and those who have scra

    • by buddyglass ( 925859 ) on Thursday January 10, 2013 @09:35AM (#42544751)
      You would be surprised at the (low) quality of some candidates whose resumes suggest they're qualified for a senior engineer position.
    • by tibit ( 1762298 )

      I don't care how senior you are. It's like saying that an experienced transplant surgeon doesn't need to know how to make an injection. Yeah, in their job probably they'll never inject anyone, but still, you need to know it just in case. Shit sometimes goes wrong. It's a wrong analogy! As for a senior software engineer: how on earth can you pretend to be able to design, you know, software, if you don't demonstrably have a clue how to, you know, make software for a very simple task? Such "senior engineers" w

    • Irrelevant? A senior engineer should be able to knock this stuff out no problem. If they cannot, then there is no way they would be able to do the job. Of course, no need to pick the obscure stuff that no one remembers, but a few basic problems just to make sure they can write some code is essential. After that, then you can discuss the intricacies of whatever specialty they happen to have. Conversation seems to draw out the advanced skills much better, however, there are loads of "expert" coders out there
    • by ShanghaiBill ( 739463 ) * on Thursday January 10, 2013 @10:43AM (#42545527)

      I personally discard any company that tests undergraduate-level stuff.

      This is one of the reasons for the test. It not only filters out the incompetent, but it also filters out the arrogant prima donnas, who will probably not be good at teamwork.

  • by jehan60188 ( 2535020 ) on Thursday January 10, 2013 @09:08AM (#42544577)

    they are as valuable as speed writing tests
    Took the GRE a year ago, and got a 0 on the writing portion since I decided to write an essay about how useless speed writing is.
    Real writing, is a very useful skill- that's when you have access to a piece of writing software that can do simple things like spell check!
    Similarly, knowing how to spit out code is not nearly as useful of a skill as knowing how to break a problem down, and decide what tools would be best for it.

    • they are as valuable as speed writing tests Took the GRE a year ago, and got a 0 on the writing portion since I decided to write an essay about how useless speed writing is. Real writing, is a very useful skill- that's when you have access to a piece of writing software that can do simple things like spell check! Similarly, knowing how to spit out code is not nearly as useful of a skill as knowing how to break a problem down, and decide what tools would be best for it.

      Gammar Nazi recommends that you upgra

  • by Ckwop ( 707653 ) <> on Thursday January 10, 2013 @09:11AM (#42544595) Homepage

    We use Fizzbuzz and a short SQL test that take a total of 30 minutes for the first part of the test. If they fail this, we can them and don't give them an interview.

    A surprising number of people fail this test.

    We then have a larger problem with much more time allotted. Here we're looking for style and quality of construction.

    That said, even with this longer test, the people we hire tend to get the same distance through the test. They're at least within the same half of an order of magnitude.

    At the end of the day, in a paid position you can and do have a deadline to work to. You can't take forever building something. You have to produce the goods!

    • by davidbrit2 ( 775091 ) on Thursday January 10, 2013 @10:02AM (#42545025) Homepage

      Yeah, give them a simple task. Something that any reasonable programmer should be able to do in 15 minutes. Then give them a solid hour to work on it. If they can't produce something working in that time, that's a pretty informative result. The time limit isn't a speed challenge; it's meant to be very generous, and act as, "Look, we need to move on..."

      Personally, I like to give a few different options from which they can choose freely. Something procedural, something OO, and maybe something in SQL or a functional language. Perhaps a couple different choices for each - around 6 to 8 total. That way you don't run the risk of excluding a worthy candidate because you happened to design some problem they aren't really specialized in, and if they can't handle any of them, that's a nice big red flag.

  • by fatphil ( 181876 ) on Thursday January 10, 2013 @09:12AM (#42544597) Homepage
    So yes, they are valid.

    I heard of one respected hi-tech company giving a 3 hour C programming task. I scribbled my solution on the back of a beermat in about 3 minutes. Were I to have been able to do it in a functional language, it would have been a 1-liner.

    I can only imagine that a 45 minute test would be "write a program which says 'hello' to the world".
  • by khakipuce ( 625944 ) on Thursday January 10, 2013 @09:13AM (#42544609) Homepage Journal

    A lot of companies use coding tests as part of the interview process and pretty much there will be some time limit, whether stated or not. They are not going to let you sit there for two days to answer 20 questions or complete a 10 line routine.

    As to the value of rigid timing, then that is a bit dubious.Do you want fast and sloppy or slow and accurate? Does this tell you something about the organisation and whether or not you want to work there? I feel it really depends on how they treat the results WRT the timing.

  • Yes (Score:5, Insightful)

    by Splab ( 574204 ) on Thursday January 10, 2013 @09:17AM (#42544643)

    If the people performing the test are any good.

    First of all it will weed out the anti authority programmers. (There is a lot of people who will refuse to do this - the door is right there...)

    Next, it will test if you can handle stress - quality of the code (should be) is irrelevant in these kind of tests. But you learn a lot about how people act under stress.

    Personal experience, during an interview I was asked to implement a hash map on a whiteboard. What they where looking for was not an actual shiny working example (hands up, those who don't need to go look in a book to find a proper hashing function (or the interwebs)) - they wanted to see how I handled myself in a stressful situation.

    • Re:Yes (Score:5, Informative)

      by SirGarlon ( 845873 ) on Thursday January 10, 2013 @10:06AM (#42545051)

      If the people performing the test are any good.

      This is a key point. I "failed" one of these interviews because my implementation updated the left-hand side of a loop condition, and the kid who was interviewing me didn't have the listening skills or mastery of basic algebra to understand that can be equivalent to updating the right-hand side.

      The take-away for me was, thank God I'm not working there with him as a colleague or, worse, a supervisor.

      This was at Google, where everyone thinks they're hot shit.

      • Similarly: I was once asked to convert a text number string to an integer value, and just jotted down the well-known textbook case example. The problem is, the efficient algorithm just goes left-to-right multiplying by another 10 each step, and the interviewer completely refused to believe that this worked (and more efficiently than his suggestion), even after I stepped him through an example. Still to this day I'm dumbfounded by that.

  • on the problem difficulty. In order _not_ to eliminate potentially good candidates, the time allocated to the interview problem should be - say - twice what it usually is for that kind of problem. The problem has to be timed, in order for the candidate to feel really involved in its solving ; it's an interview, not a school.
  • by Anonymous Coward

    To find completed code for that assignment online.

  • by drolli ( 522659 )

    Somebody with a complete education must be able to solve an undergrad problem without thinking much, just sytematically applying knowledfge and understanding.

    In the same way in which anybody can expect that I (Phd in physics) will solve a decay equation correctly without trying aroung for hours or set up a equation of motion for a dynamical system without looking up for hours in textbooks (i am at least supposed to know where to find the solution), i expect that a self-announced programmer is able to write

  • Sure it does (Score:3, Insightful)

    by beinsvein ( 2752465 ) on Thursday January 10, 2013 @09:26AM (#42544703)
    If a job requires a skill that is easy to test, it should be obvious that you want to test it. Programming is such a skill. Sure there are tasks within programming that can't be tested in 45 minutes, but there are also tasks that can. I'd feel I knew more about a programmer's skills having seen a couple dozen lines of code she's written than for instance hearing her last employer's opinion, which may be biased by all sorts of interests, or reading the list of projects she'd worked on, where you don't know how she contributed. College grades in programming courses might provide the same kind of information, but courses may not be standardized and the candidate might have developed her skills since college.
  • Heck yes (Score:5, Informative)

    by dkleinsc ( 563838 ) on Thursday January 10, 2013 @09:28AM (#42544709) Homepage

    The basic rule of programming interviews is that you should demand that they actually program. It doesn't necessarily have to be a difficult problem: I've handed somebody a standard Fizzbuzz in an interview, and the competent candidates will solve it in 2-5 minutes, while the incompetent candidates won't solve it in 15 minutes.

    The reason this is necessary is that on paper, the incompetent candidates can look identical to the competent candidates.

  • by mykepredko ( 40154 ) on Thursday January 10, 2013 @09:28AM (#42544715) Homepage

    When I was at RIM, we used a broken quick sort method that the candidate was asked to fix. We didn't time how long it took the candidate to implement the fix, but it generally required the candidate to do some research as to what was wrong. One of the team leads created a simple app that tested the performance (ie speed) of the fix.

    What was really interesting to me was the number of candidates who refused to do the test (50-60%) because they said it was "beneath them". The big problem was, RIM's HR (OD) that insisted we interview the candidatest that refused to do the test because we were losing potentially half the candidates that were responding to the job applications (this was when RIM was The Place To Be).

    The best candidates were the ones that did the test and asked if we had any more. These candidates also tended to produce code that ran sort the fastest.


  • I would say a highly time-constrained exercise is not so useful since it will disqualify some candidates who might otherwise turn out to be valuable developers. That said, I think a non-highly-time-constrained coding exercise could be a very valuable tool. If you give a guy four hours to code up something that should take about two and it still has terrible bugs or the code is complete spaghetti (or he doesn't finish in the first place) then you can be pretty sure he's not someone you want to hire. This
  • by clickety6 ( 141178 ) on Thursday January 10, 2013 @09:30AM (#42544725)
    But they should shorten the limit to 10 minutes or less.


    It shouldn't take any competent programmer more than a few minutes to google some fitting example code, rename a few variables and update the comments :)

  • Unless the problem is so easy, or the time limit so relaxed as to be irrelevant, testing speed definitely tests some sort of skill(it sure as hell isn't joe codemonkey who wins those speed-coding competitions); but whether it tests a relevant skill is somewhat less clear and more job-dependent.

    If you are hiring people to program something of any significant size, you will have time/deadline issues; but they will be less of the "Bob can't get a bubble sort written in less than 40 minutes!" and more of the 'a

  • Timed tests would only stress me out to the point where I would probably code poorly due to worrying about the clock. I suppose it depends on the difficulty of the project of course. If it's say a few hundred lines of code I could do that maybe an hour or so. If it's less than that then I could do it even quicker.

    How many lines of code? How complicated are we talking about? What language is it in? If it's something like Python I could for sure write a web browser or some kind of bot in 100 lines of code in

  • by assertation ( 1255714 ) on Thursday January 10, 2013 @09:44AM (#42544855)

    I've been programming for about 14 years. I have seen this conversation come up plenty of times. Many people come up with good reasons why such programming tests and other programming job interview techniques unfairly weed people out. I've been a victim of it myself at some interviews and have gone on to do STELLAR work at OTHER places. The bottom line is that employers feel that they need SOMETHING, even something crappy, so... these interview tests are a fact of life.

    However misguided, if you are a programmer and you want a new job, you have to deal with this reality.

    Fortunately, in 2013 there are a plethora of programming interview prep books out there so at least you have a chance if somebody throws a pop quiz at you about the tower of hanoi, asks you to write a script to print out only prime numbers or asks you to write a script to reverse a string using no speciality functions though you have not thought about such mishigas in years.

    • by tibit ( 1762298 )

      I don't know what tests you're alluding to, but man, if you can't do fizzbuzz-style exercise without breaking a sweat, you're useless, okay? I don't even think there's any argument to that. When you're designing large systems, you must have demonstrable working knowledge of the basics. Otherwise your designs will be bloated monsters where anyone who knows their basics will look at and say: it took you HOW LONG and HOW MUCH MAN-YEARS?!

      Fact of life: if you don't have a decent grasp of basics of computer scien

  • Deadlines (Score:3, Insightful)

    by wisnoskij ( 1206448 ) on Thursday January 10, 2013 @09:52AM (#42544933) Homepage

    Are you telling us that you have never heard of job deadlines before?

  • by ledow ( 319597 ) on Thursday January 10, 2013 @10:21AM (#42545239) Homepage

    1) No recruitment process mirrors what is required in the job. Don't expect it to.

    2) Most recruitment processes generate only a single metric in a particular way.

    3) That metric may not be what you think ("What did he do in the last ten minutes of the impossible task we set? Panic? Make stuff up and waffle? Or state that the problem required further time and an interesting avenue for development seemed to be X?" - you'll probably find that your code ends up in a bin within minutes of the test after a brief "Yeah, looks reasonable" check)

    4) That metric, if it IS the sole basis of the recruitment process, will result in candidates being hired who are good at that metric, not the job (e.g. managers who are good at bullshitting other managers rather than managing, coders good at churning out stuff that looks right but is horrendous to use or wrong, etc.). If that's the case, you won't get the job, and wouldn't want to work there if you did (those people would be your co-workers, and your managers would think they'd done a good job of hiring them in the first place, and wonder why you have a problem with them).

    5) The bulk of the recruitment process otherwise is about weeding out the chaff so they have more time to talk to YOU and find out whether you're actually suitable. Large companies get idiots who can't turn a computer on apply for datacentre systems administrator posts, and the test is there to save them time. Cut out the chaff, get a handful of candidates worthy of interview from THOUSANDS who applied (CV's written in crayon or with spelling mistakes = first stage bin, people who don't have relevant experience / qualifications = second stage bin, people who don't turn up to interview, or turn up late or scruffy = third stage bin, people who can't pass the test = fourth stage bin, the rest are interviewed properly - it's quite easy to get to the interview stage, or to manage the applications up to the interview stage, knowing NOTHING about the job at all).

    6) I would hire the guy who approaches me on the day of the test and quietly says "I don't think that's enough time, but I'll try my best, okay?" if he has one ounce of relevant experience / qualification / skill.

  • by jnelson4765 ( 845296 ) on Thursday January 10, 2013 @10:49AM (#42545601) Journal

    I've done one recently - it also tests memory and grace under pressure. Some people just can't perform well under the gun, and in a high-pressure workplace where you may be dealing with outages that are hitting the tech press within minutes, and the global press within an hour, being ale to not fold under pressure is a critical job skill.

    Plus, as my old business computing teacher in high school said, "You will be doing tasks that make no sense on obsolete technology for inscrutable reasons. If you have a problem with any of this, you should probably drop out of this class, since you do not have what it takes to be a programmer in the business world." Dealing with arbitrary requirements is part of working for any large company, and seeing if an applicant will go through with it, or if their ego is going to get in the way, is a useful test.

  • But the curious thing is that I've never, ever, seen them given to contractors, only permies.

    Given that contracts are (IME) composed of the best and the worst, but bill you the same either way, this would be the group to which I'd mostly like to say "You want money? Show me."

  • by TheGratefulNet ( 143330 ) on Thursday January 10, 2013 @12:16PM (#42546769)

    ob disc: I'm an older guy (50's) and have been writing C code for almost all my jobs in my life since my early 20's. I write code at home, I develop firmware (and hardware, also at home) and I'm extremely technical.

    but I fail a lot on 'programming timed tests' and I blame my older slower mind, mostly. the last time I HAD to get inside a tree data structure and totally rewrite it: never in my life. the last time I had to implement a sort routine from scratch: never in my life. its always been a matter of consulting the standard ref models, adapting them and using them. its simply not real-world to test memory recall.

    younger guys (I was one once, lol) have an advantage. its fresh in their minds, and they don't have 35+ years of 'noise' in their brains for those sort/search/traverse routines to compete with. I remember when it was trivially easy to derive those algs on the spot or recall them from memory. I passed almost every coding test back in the 80's, 90's and even 00's. but now, I'm finding I have to sit back, think, maybe search a bit and then I can get the answer.

    interviewers who are in their 20's and 30's have no patience for people like me. I bet they even laugh behind my back. and yes, speed DOES definitely change as you get older.

    but put me in a real life situation where I DO have net access, emacs, gcc and gdb and I'll get your answer pretty quickly and demo it to you, too, if you want.

    in summary, real life is an open-book work style. testing candidates closed-book style really reflects badly on YOU, the interviewer, for not getting this detail about how young vs experienced people think and solve problems. for the new guys, you can only ask them the datastruct101 level questions. but its wrong and even insulting to ask older guys the same questions and in the same way, expecting the same speed of reply.

    when I interview with older guys, they 'get it' and they aren't such hard-asses. they know what matters, there is respect and it shows. I like interviewing at places like that. they have human beings there.

    but 'compare dick sizes' interviews, where the company guys are there mostly to show off and try to knock you down (I'm looking at you, google...) are a waste of everyone's time and fairly insulting, at that.

    I would almost go so far as to say that its improper to have a 20something interview a 40 or 50something. they have no idea what to ask, how to gauge the reply or value it and it often comes off as a strange young/old challenge.

    anyway, I will not pass any coding speed tests. but I can always solve the problem, I can learn 'on the fly' as I research the problem and I know enough to avoid the bad algs and target the efficient ones. I just don't -care- about deriving the fundamental building blocks anymore. I USE the blocks, I'm kind of tired of looking inside them. (I build electronics quite a bit but I'd never be able to answer exactly how an NPN is built, nor do I need to care to be able to effectively use it).

    companies that apply speed tests have missed the point. it shows poorly on them, in fact, that they think this actually makes sense.

  • by TheSkepticalOptimist ( 898384 ) on Thursday January 10, 2013 @02:14PM (#42548407)

    Do you want to work for a company that values hiring its employees on whether they can write code under pressure? No properly managed tech company should ever have a culture of stressful, high pressure, time based code development.

    I know a lot of people feel that in an interview they are the ones under scrutiny, but realize that there is a shortage of quality developers (but an abundance of wannabees) out there and you really should also be scrutinizing the company you are applying for. Making the mistake of only trying to be an attractive candidate without also attempting to "interview" the interviewer is the biggest rookie mistake any person makes when looking for employment.

    I have been to several interviews where I basically realized within 5 minutes that the company had their heads up their asses when it comes to finding talent. If a company is unable to adequately interview for talent then you can only imagine how poor the state of the quality of their management and leadership is in the company. I know a lot of people blame HR, but poor HR only results when managers and directors are unable to adequately convey the talent and skill requirements they are looking for, so HR staff have to make up the job description and interview process.

    Also, with over 12 years experience, I get really frustrated when being interviewed for a senior level position only to have to answer a bunch of junior level questions about coding. I know how to code, and it should be assumed I know how to code from my work history, how about asking me high level architecture questions, how to apply software patterns, or how to create efficient software process. I've moved away from being a code monkey and have been responsible for designing, architecting and overseeing development of entire applications, don't ask me what passing a value by reference means or how to write a recursive method, that just means you don't deserve my experience..

I've noticed several design suggestions in your code.