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How Effective are Technical Interviews?

jeanhsu.com

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Re: How Effective are Technical Interviews?

#61

Post by rhizome »

tptacek wrote: post #39
sophacles wrote: post #25

I have found that for technical interviews, the following pattern works very well (hiring side): 0. Explain to the candidate this algorithm and why. It isn't magic, there are no right or wrong answers, just testing "fit". This is a case where foreknowledge does not change the outcome! 1. Get a basic grasp of technologies both interviewer and candidate have in common, via say, just chatting. This is vital -- find an a…

I have over the last 8 years or so become terrified of interviewing techniques that revolve around having a conversation with a candidate, even (or, in fact especially) directed conversations. Like many others before me, I've discovered that there is a huge gap between the ability to talk intelligently and productively about solving programming problems, and being able to actually solve programming problems. It's fin…

But does that perceived gap mean that your technique is actually better for the company? I'm seeing a false dichotomy here where those who can talk about code can't write it, and those who can write code are inarticulate. I have a nagging feeling that being "terrified of...conversations" supplies a bit of confirmation bias to your technique.

Re: How Effective are Technical Interviews?

#62

Post by ultrasaurus »

narag wrote: post #43
sophacles wrote: post #25

I have found that for technical interviews, the following pattern works very well (hiring side): 0. Explain to the candidate this algorithm and why. It isn't magic, there are no right or wrong answers, just testing "fit". This is a case where foreknowledge does not change the outcome! 1. Get a basic grasp of technologies both interviewer and candidate have in common, via say, just chatting. This is vital -- find an a…

This method has made me remember an old interview (1998) and smile. The interviewer started explaining what I'd be working on. In a few minutes it wasn't an interview anymore, but a free consulting session. He clearly forgot why we were there and even started to take notes! I was offered the job, but later refused because another offer was better.

I love interviews like this. I imagine most people on HN like solving problems and it answers the question "will this person bring anything to the org?"

Re: How Effective are Technical Interviews?

#63

Post by kirbman89 »

sophacles wrote: post #25

I have found that for technical interviews, the following pattern works very well (hiring side): 0. Explain to the candidate this algorithm and why. It isn't magic, there are no right or wrong answers, just testing "fit". This is a case where foreknowledge does not change the outcome! 1. Get a basic grasp of technologies both interviewer and candidate have in common, via say, just chatting. This is vital -- find an a…

Brainstorming on a problem together is mutually beneficial. That really strikes a chord with me. I'd rather get to know the person that I might be working for than a boring question-answering session or worst yet writing pseudo code for recursion.

Re: How Effective are Technical Interviews?

#64

Post by strlen »

kscaldef wrote: post #54
dkarl wrote: post #49

Many technical interviews are very theory-heavy, muddling the divide between Computer Science and Software Engineering. I've been faulted for this in my interviewing, but I think that you have to pose at least one problem that can be explained precisely in less than a minute and solved completely in less than an hour. Such a problem will inevitably have an abstract, theoretical feel. It's also good to ask more realis…

In my experience, people start complaining that an interview is "theory-heavy" at about the point that you expect them to know when and how to use a binary tree. Binary trees are not hard-core CS theory, they are freshman Intro to Data Structures. They are a very basic tool (almost) every programmer should be familiar with. Moreover, when I ask candidates questions about data structures and algorithms, while it's nic…

> In my experience, people start complaining that an interview is "theory-heavy" at about the point that you expect them to know when and how to use a binary tree. Binary trees are not hard-core CS theory, they are freshman Intro to Data Structures.

The other part about binary trees is by their very nature they involve pointers and recursion. Understanding pointers and recursion is the difference between being able to write code and being a programmer. The former is a fundamental skill any knowledge worker should have (scientists and financiers using Matlab or Python, statisticians using R); the latter takes passion, effort and talent.

The other extreme I've seen is asking questions from computational geometry, combinatorics and complexity theory (for generalist software engineering positions). These are all relevant skills and for the former two a good cursory knowledge is important for a generalist: however, unlike pointers or recursion they're not as fundamental to programming.

Re: How Effective are Technical Interviews?

#65

Post by varjag »

fendale wrote: post #42
varjag wrote: post #29

Earlier quoted context omitted.

Well, itoa() stands for "integer to ASCII". You can use the property of sequential numbers (starting at 0x30 in ASCII table) to avoid the case statement.

Good point, I actually thought of doing that and then dismissed it. Maybe the best perfoming way would be to use the remainder as the index to an array (suggested in another comment)?

It's C we talking about, just add the remainder to 0x30 and you get your character.

Re: How Effective are Technical Interviews?

#66

Post by VladRussian »

tocomment wrote: post #4

I like interviews where you explain existing code you've written. I do well with those. I also do well if they give me a homework problem before the interview. True story. Interview at Google. They had me make this AJAX web application as homework before the interview. Three people told me they LOVED my solution and thought it was beautiful. I figured I was a shoe-in for the job at that point. But at the interview th…

i think you failed the whole interviewing process when you agreed to complete and did complete the _unpaid_ "homework".

Re: How Effective are Technical Interviews?

#67

Post by imajes »

patio11 wrote: post #20

I put tech interviews down fifty/fifty to "We don't know any better way of doing this" and "The unavoidable reality is that if a position is advertised openly then 98% of candidates are screamingly inappropriate for it and after applying a few filters to the resume we've gotten that to a more manageable 90% or so for interviews." Happily, there is a simple opt out mechanism. There are two ways to get into any company…

I've picked door number two consistently throughout my career. It's more effective and much more meaningful to establish a relationship with decision makers from the get go.

Re: How Effective are Technical Interviews?

#68

Post by fleitz »

I prefer interviewing with koans. Setup a workstation with the tests and get the interviewee to make them pass.

Have the interviewee check them into git / SCM on their own branch. It tests so much day to day knowledge and the ability to actually code / read code / and find / fix bugs.

As well as all the various issues with your particular stack. Plus you can hide bugs all over the place, maybe the bug is in the database, etc. Maybe it's a real world task like 'speed up this page by 200%' type thing. There is a lot of flexibility and provides opportunity to for insight into how the developer actually solves real world problems. Maybe the increase the logic speed by 200%, maybe they just throw varnish on top of it.

Re: How Effective are Technical Interviews?

#69

Post by tocomment »

eli wrote: post #23
tocomment wrote: post #4

I like interviews where you explain existing code you've written. I do well with those. I also do well if they give me a homework problem before the interview. True story. Interview at Google. They had me make this AJAX web application as homework before the interview. Three people told me they LOVED my solution and thought it was beautiful. I figured I was a shoe-in for the job at that point. But at the interview th…

I once tried giving out a homework problem to interviewees and a surprising number of people flat-out cheated! I absolutely hate "trivia" questions, but I feel like I have to ask people to actually write code during an interview even though it's unrealistic and a bit unfair. (I also think that if a candidate is flying to the interview, the employer should cover the airfare... but maybe that's why I don't get to hire…

How did people cheat? It seems like if you ask them to create or solve something that hasn't been done before they'd have to figure it out.

Of course they could get someone to write the code for them but A. You can catch that by reviewing the code with them and asking questions and B. If they can get someone to write good code for them And then review that code to make sure it's good you might want to put that person in managment.

Re: How Effective are Technical Interviews?

#70

Post by kenjackson »

sophacles wrote: post #25

I have found that for technical interviews, the following pattern works very well (hiring side): 0. Explain to the candidate this algorithm and why. It isn't magic, there are no right or wrong answers, just testing "fit". This is a case where foreknowledge does not change the outcome! 1. Get a basic grasp of technologies both interviewer and candidate have in common, via say, just chatting. This is vital -- find an a…

The problem with this, IMO, is that it is really soft. Some research has shown we make up our minds within the first 10s (or so) of an interview if we like the person. And the rest of the interview justifies this decision.

I have to have some "minimum" requirement questions. These are questions that you have to get right. No matter how good I feel about you, I still will no hire you if you get these questions wrong. These are questions that are so easy that most people on HN would scoff me even asking. Yet it actually does eliminate some people.

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