topic Re: Favorite screening interview questions in BreakPoint

Favorite screening interview questions

BowenM — Thu, 19 Oct 2017 20:30:58 GMT

I saw this thread, but didn't feel like dragging it back up.

So, we've been trying to hire for 2 positions now for awhile and we always do a 30 minute phone screen. I usually only get a single question to ask that will say "yes this person likely knows LabVIEW" or "nope, don't bring them in." So, for those of you that have interviewed candidates, what are some of your favorite single screening questions?

Personally, I initially started with something simple - CLAD type questions. "Tell me an example of when you would use a shift register", etc. but it wasn't very reliable.

I have since switched to: "What is your favorite architecture and why?". My thought is that if they know enough about LabVIEW to at least know the most common architectures it's likely worth bringing them onsite.

Anyone have any others?

Re: Favorite screening interview questions

Hooovahh — Thu, 19 Oct 2017 21:15:43 GMT

I like to ask them "What is reentrancy in reference to a VI and when would I use it?" It isn't a subject a beginner will be too familiar with, and it is a somewhat LabVIEW only feature. Asking something like what architecture do you like could be answered with a state machine or producer consumer, or publisher subscriber. Which are fine answers but most CS students could answer that with no LabVIEW experience. That being said you can know what reentrancy is and be a bad LabVIEW programmer so my follow up question is usually "Do you know who hooovahh is?"

Just kidding I'm not that pompous.

Re: Favorite screening interview questions

Gregory — Thu, 19 Oct 2017 21:25:13 GMT

I think the question about architectures is a good one, although a little open ended. A phone interview is especially challenging, if you cannot find a way to both be looking at the same block diagram for some questions. One place I applied to sent me to an online portal where I took a a CLAD style exam, I don't know if that is an option for you.

Related to architectures, I've found a large gap in skill between people who know how to pass data between loops and people who don't. If they only mention local/global variables and property nodes, they probably have a lot to learn. If they mention queues and notifiers and can explain that "enqueue element" puts an item on the queue and "dequeue element" takes it off then they are a bit more advanced. If they know about user events and how to generate an event and handle it with the event structure, then they probably know their stuff.

When I was interviewing people in person I would usually finish with a block diagram that looked like producer / consumer (events) where the consumer loop could communicate an error to the producer with a user event. I would ask "how is data sent from the bottom loop to the top loop?" Even a guy who showed off some impressive sequencing code and claimed everyone calls him "the LabVIEW guy" just stared blankly at the diagram... 😞

On the application you can ask if they are active in any LV forums or have certifications. I absolutely believe you can write great code without a LV certification, but it is nice to have a baseline to go off of when interviewing someone!

Re: Favorite screening interview questions

Jacobson-ni — Thu, 19 Oct 2017 23:50:18 GMT

Don't have a specific question, but I think you can tell how experienced someone is with LabVIEW by what and how they complain about LabVIEW. I talk to a lot of different users with varying amounts of experience and it's something I've noticed.

If someone doesn't have a lot of experience, they tend to complain about non-issues. Like, for complex projects, VI diagrams tend to get large and become difficult to navigate/manage. The competent developer might complain about something like LabVIEW locking classes which get loaded under multiple targets in a project or how exiting many parallel processes gracefully can be tricky. And, of course, you know that the very experienced LabVIEW programmer will launch into some impassioned tirade about some very specific detail.

Re: Favorite screening interview questions

thoult — Fri, 20 Oct 2017 08:43:54 GMT

What architectures have you used, and why?
- Silence at the other end of the phone is usually the beginning of the end of the call
- Even if they're single loop programmers, awareness of other architectures is a good sign
What hardware have you interfaced with, and how?
- Any NI hardware? Have they used RT and FPGA?
- Any third party hardware? Have they used .NET or ActiveX? Have they used VISA?
What experience do you have in working with electronics or mechanics?
- Do they think they can debug a simple circuit? Can they use an oscilloscope? Can they provide requirements to a PCB designer?
- Can they understand the mechanical components of a test system? Can they liaise with mechanical engineers?
- I like LabVIEW engineers, but I prefer system engineers who can interact with specialists
Do you use any sort of source control? If so, how has it helped you? If not, can you see how it could help?
- This is one of the steps to enlightenment in software development
- You might have to explain the concept to some, but they should be able to join the dots and see that collaborative working, traceability and retracing your steps in the event of catastrophe are all benefits
If you don't know how to solve a problem in LabVIEW, how do you figure it out?
- The things I want to hear are Googling, using the NI forums, using examples, talking to a more experienced colleague, using AE support at NI...but I want to hear a few options
- Problem solving is an important skill that is hard to judge in interviews...but at least get them showing that they can approach problems in different ways over the phone
Do you work with any other developers, or see anyone else's code? How do you rate your experience and skillset?
- I don't mind people who've been lone wolves, but an unswerving belief that your skills are excellent having not had anyone else to benchmark against is usually a warning sign
- I like people who want to learn and expand their skills, so a bit of self realisation that there are areas to improve in is always welcome
What do you like to do away from work?
- Like a CAPTCHA, are you a robot?

Just a few thoughts off the top of my head. In general, try to ask open ended questions and let them talk about their work, skills and experience.

Re: Favorite screening interview questions

BowenM — Fri, 20 Oct 2017 13:12:01 GMT

@Jacobson-ni wrote:

Don't have a specific question, but I think you can tell how experienced someone is with LabVIEW by what and how they complain about LabVIEW. I talk to a lot of different users with varying amounts of experience and it's something I've noticed.

I like that idea a lot... tell how competent someone is at LabVIEW by asking them to complain about it. A question something along the lines: "Every programming language has its strengths and weaknesses - and LabVIEW is no exception. What are some of the weaknesses you think LabVIEW has?"

Re: Favorite screening interview questions

jcarmody — Mon, 23 Oct 2017 19:59:14 GMT

@BowenM wrote:

[...]
Anyone have any others?

"What's your ni.com user name?"

"What's your LAVA user name?"

Do you use the CaseSelect QD plugin?

Re: Favorite screening interview questions

Hooovahh — Mon, 23 Oct 2017 20:33:49 GMT

@jcarmody wrote:
Do you use the CaseSelect QD plugin?

I do (just not often). When Jim and his gang were showing off the JKI State Machine Editor, I called it CaseSelect++ and got a few chuckles.

Re: Favorite screening interview questions

JÞB — Mon, 23 Oct 2017 21:03:08 GMT

My favorite is: "Hey Jeff! are you available?"

Re: Favorite screening interview questions

PeterFoerster — Wed, 25 Oct 2017 13:14:09 GMT

If you have the possibility to show them something, a small code sample can help assess their skill level.

This is something I've used to test people fresh from college that claim to know LabVIEW.

Question one: What is result?

Question two: What is result the second time? (or better: Obviously, it's the same every time I execute this, isn't it?)

It's certainly not too hard, but it shows you if someone knows basic concepts, like auto-indexing and uninitialized shift registers. Really depends on what level you want to test.

Re: Favorite screening interview questions

altenbach — Wed, 25 Oct 2017 15:27:33 GMT

@PeterFoerster wrote:

Question one: What is result?

The result is unknown (first and second time), because unless the array shows the first element that is out of range, we cannot tell from a picture what the array size of the constant is. It could contain millions of values. Container size != array size in general.

This is my final answer! Do I get the job?

Of course you could ask the applicant if there is anything special about this code picture. For example ask what these glyphs in the upper left mean or why it has a dotted outline? What would he do to transfer that code into LabVIEW as quickly as possible? 😄

Re: Favorite screening interview questions

Ben — Fri, 27 Oct 2017 12:36:44 GMT

@Hooovahh wrote:

@jcarmody wrote:
Do you use the CaseSelect QD plugin?

I do (just not often). When Jim and his gang were showing off the JKI State Machine Editor, I called it CaseSelect++ and got a few chuckles.

Please correct me if my memory has failed me but wasn't it "jcarmody" that developed that Plugin ?

Ben

Re: Favorite screening interview questions

jcarmody — Mon, 30 Oct 2017 12:55:18 GMT

@Ben wrote:

Please correct me if my memory has failed me but wasn't it "jcarmody" that developed that Plugin ?

Ben

You're correct, and I released it to the world under a BSD license. Jim Kring contacted me about extending, packaging and releasing it and I was happy to oblige. JKI added a few features (and significant credibility) and shared it with a larger audience than I was able to reach.

Re: Favorite screening interview questions

BowenM — Wed, 01 Nov 2017 14:46:43 GMT

Jacobson wrote:

Don't have a specific question, but I think you can tell how experienced someone is with LabVIEW by what and how they complain about LabVIEW. I talk to a lot of different users with varying amounts of experience and it's something I've noticed.

This is now my favorite question hands down.

I had someone the other day claim several years' experience developing and was able to answer some simple questions like "what is a shift register" but when asked what he didn't like about LabVIEW gave an answer along the lines of "VIs have a tendency to become too large and hard to follow".

Re: Favorite screening interview questions

cfactorllc — Mon, 18 Dec 2017 15:13:53 GMT

CLA, this is excellent, thank you for posting these interview questions! bob v

Re: Favorite screening interview questions

BowenM — Mon, 18 Dec 2017 22:27:49 GMT

Ya there were some good questions posted here.

@JÞB wrote:

My favorite is: "Hey Jeff! are you available?"

Except that one. I tried it - it didn't work.

Re: Favorite screening interview questions

JÞB — Tue, 19 Dec 2017 14:49:27 GMT

@BowenM wrote:

Ya there were some good questions posted here.

@JÞB wrote:

My favorite is: "Hey Jeff! are you available?"

Except that one. I tried it - it didn't work.

It worked fine. It was just that you weren't the only one asking that question.