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Ask Slashdot: Are Timed Coding Tests Valuable?
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?"
I dunno...but it will weed out the pretenders/bullshitters.
No sig today...
They are extremely valuable - they let you know which potential employers don't have a clue about programmer productivity / expertise.
Bogtha Bogtha Bogtha
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!
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.
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.
Art is the mathematics of emotion
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.
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.
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.
I am officially gone from
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.
myke
Mimetics Inc. Twitter
You would be surprised at the (low) quality of some candidates whose resumes suggest they're qualified for a senior engineer position.
Funny how you misspelled "Gammar Nazi"
The thing is, you may not be hiring a worldwide known linux kernel expert. You may instead be thinking about hiring someone who's CV says he's done several impressive looking things. You need to verify what his level of involvement in those was, and a good first step is often "are you so retarded that you can't possibly be telling the truth on your CV".
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.
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.
Why can't I mod "-1 Idiot"?
When I'm hiring for positions that are paying high salaries, I want to know the person is just as good (or better) in front of a computer as they are at interviewing and sounding smart. A simple programming exercise can confirm that the person is good with computers, not just as BS'ing their way through interviews.
It's disappointing how many applicants will fail such a simple demonstration of their claimed skills. Likewise, if someone thinks a short demonstration is beneath them, I don't want to work with them. Every job has some crap that just needs to be done, even if its a waste of everyone's time. If they haven't learned the "do it and move on" philosophy, they're going to be hard to work with. I've worked with people who will spend days arguing against doing 20 minutes of work - I'm definitely not going to hire people like that.
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.
--
"It is now safe to switch off your computer."
And I understand the pompous arrogance that motivates his feigned ignorance at the purpose of fizzbuzz tests. For every apocryphal story of "zomg they asked me to write quicksort from memory!" there are hundreds of actual examples of people with impressive credentials who can't even handle modulo arithmetic or linked lists or whatever trivial concept most competent programmers know reflexively. I know, early in my career I graded the damn things, and flunked several people with Masters degrees and many people with years of experience. Never failed a PhD's test, but I did witness one guy who stormed out of the interview when asked to take one. Buh-bye, cupcake!
No one is above this. Anyone who believes they are too special to take it is either so completely ignorant of the industry and the caliber of applicants that they won't perform well in a business setting, or, more likely, they are aware of their own shortcomings and are putting on a show to maintain face and self-esteem. Competent people use them as an opportunity to relax and maybe show off a little.
Seriously, refusing a fizzbuzz test for a programming job is like applying at the DEA and refusing the mandatory drug test. I don't care how you feel about it, you're a fucking a moron to think you could ever get around it.