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Ask HN: coding challenges as part of interviews: yes or no?

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Ask HN: coding challenges as part of interviews: yes or no?

#1
just curious what the group thinks of coding quizzes / challenges that are often part of job interviews for programmers. how predictive are they of a coder's future performance? are they appropriate only for entry level positions (when someone has less industry experience), or are they suitable for any level? are they more likely to pique your interest or to come across as cliche?

Re: Ask HN: coding challenges as part of interviews: yes or no?

#2
Trick questions, or questions with some kind of gottcha have no place in interviews, However, simple, straightforward programming exercises are essential. I've seen people who claim to have X years of industry experience who can talk a good game, but literally can't write a switch statement without reference to the internet.

I also like to ask people to peer review some code with both obvious and more subtle errors in it. That's a pretty important skill to me too. Anyway, ask them to code some fairly simple algorithm and then critique their own work. If there are several ways to solve the same problem, some more efficient than others, all the better.

Re: Ask HN: coding challenges as part of interviews: yes or no?

#3
Programming challenges sort the wheat from the chaff - in particular those who cannot code at all, but beyond that I've rarely found them predictive of future performance. Much more important that you hire a good fit for your company. An unhappy or toxic coder can bring a startup to its knees - hire slow, fire fast and all that.

Re: Ask HN: coding challenges as part of interviews: yes or no?

#4
post #2

Trick questions, or questions with some kind of gottcha have no place in interviews, However, simple, straightforward programming exercises are essential. I've seen people who claim to have X years of industry experience who can talk a good game, but literally can't write a switch statement without reference to the internet. I also like to ask people to peer review some code with both obvious and more subtle errors i…

Hmm... I know > 10 languages. I'm not sure I could remember the exact syntax in several of those languages on the spot. Is it case, is it switch, etc. If you do this, your test is on rote memorization.

Give them a novel problem and have them solve it with a real computer and in tact syntax lookup. Then see what and how they did it and go over their reasoning. I'll hire the guy with the wisdom over the guy who can spit out syntax trivia flawlessly. Those are different skill-sets that do not predict each other.

Re: Ask HN: coding challenges as part of interviews: yes or no?

#5
post #2

Trick questions, or questions with some kind of gottcha have no place in interviews, However, simple, straightforward programming exercises are essential. I've seen people who claim to have X years of industry experience who can talk a good game, but literally can't write a switch statement without reference to the internet. I also like to ask people to peer review some code with both obvious and more subtle errors i…

I agree wholeheartedly with the above. Gotcha questions are nice if you value having a sense of superiority over your candidates. Seeing how someone approaches a simple coding exercise tells you a lot about their techniques.

Two examples stand out:

1) A guy who had more Java certifications than had eaten hot dinners couldn't complete the simple exercise after three or four hours of effort.

2) Guy initially attempted to hit Google up for examples (why not!), and on finding that the net connection was disabled for that user account, wrote the best solution to the exercise I've received.

Overall, my interviewing process has had two stages. First, talk to the candidate and get a sense of what kind of person they are, and if they'll fit in with the culture. Second, if they seem reasonable, give them the test and see what their code is like. It's not foolproof, but it does weed out most of the weaker candidates.

Re: Ask HN: coding challenges as part of interviews: yes or no?

#6
Agree with jamess, but additionally, I think interviewers that don't ask coding questions might be an indication of something negative at the company. Basic coding ability has to be one of those checkbox questions that determines your eligibility for the position, and if the interviewer doesn't ask anything technocal, it makes me wonder what kind of dumbasses I might end up working with.

Re: Ask HN: coding challenges as part of interviews: yes or no?

#7
post #2

Trick questions, or questions with some kind of gottcha have no place in interviews, However, simple, straightforward programming exercises are essential. I've seen people who claim to have X years of industry experience who can talk a good game, but literally can't write a switch statement without reference to the internet. I also like to ask people to peer review some code with both obvious and more subtle errors i…

Some questions do let you guage how the person responds to stress and unknown environments - that may be helpful.

Re: Ask HN: coding challenges as part of interviews: yes or no?

#8
post #4
post #2

Trick questions, or questions with some kind of gottcha have no place in interviews, However, simple, straightforward programming exercises are essential. I've seen people who claim to have X years of industry experience who can talk a good game, but literally can't write a switch statement without reference to the internet. I also like to ask people to peer review some code with both obvious and more subtle errors i…

Hmm... I know > 10 languages. I'm not sure I could remember the exact syntax in several of those languages on the spot. Is it case, is it switch, etc. If you do this, your test is on rote memorization. Give them a novel problem and have them solve it with a real computer and in tact syntax lookup. Then see what and how they did it and go over their reasoning. I'll hire the guy with the wisdom over the guy who can spi…

Agreed. My first job they gave me a copy of Deitel & Deitel's "C How to program" along with the test. You actually lost points if you didn't open it!

Re: Ask HN: coding challenges as part of interviews: yes or no?

#9
post #8
post #4

Earlier quoted context omitted.

Hmm... I know > 10 languages. I'm not sure I could remember the exact syntax in several of those languages on the spot. Is it case, is it switch, etc. If you do this, your test is on rote memorization. Give them a novel problem and have them solve it with a real computer and in tact syntax lookup. Then see what and how they did it and go over their reasoning. I'll hire the guy with the wisdom over the guy who can spi…

Agreed. My first job they gave me a copy of Deitel & Deitel's "C How to program" along with the test. You actually lost points if you didn't open it!

You know the syntax of switch in the language you have been using in the last three months. If you don't, something's wrong!

Re: Ask HN: coding challenges as part of interviews: yes or no?

#10
post #6

Agree with jamess, but additionally, I think interviewers that don't ask coding questions might be an indication of something negative at the company. Basic coding ability has to be one of those checkbox questions that determines your eligibility for the position, and if the interviewer doesn't ask anything technocal, it makes me wonder what kind of dumbasses I might end up working with.

Indeed, whether candidates write code during their interview is one of the items on the Joel Test (http://www.joelonsoftware.com/articles/fog0000000043.html).
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