How (not) to interview – part II

After writing the first article I was left with couple bits that I wanted to mention but they didn’t quite fit. So I have decided to write up a short follow up where I will outline what I think would be the ideal process and some other notes on questions commonly asked. 

The process

The most important is clarity so there are clear and managed expectations. So in my opinion the process should be:

  • published and available to candidates prior application for the role
  • should have clearly defined time-frame
  • should be at most 3 stages
    • phone interview with some basic screening
    • face 2 face/webex  with technical test and soft skills test
    • optionally additional meeting with higher up managers
  • should be gated so failure on any stage or sub-stage should mean termination of the process

The last point might sound a bit harsh but if each stage of the interview has a clear pass/fail criteria that are directly communicated (e.g. a test score) this approach save you and the candidate lot of time while it doesn’t set wrong expectations.

Also the technical part should be clearly communicated and marked so there  is no space for any doubts.

The technical questions

This is a topic that could on it’s own be a series of articles but I will just note down some things that I’ve noticed recently around this topic. This is by no means exhausting list but more of couple thoughts on couple of questions I had seen/heard/asked recently.

Ideal short question for phone interview is one that leaves next to no space for misinterpretation and forces the candidate to answer fairly directly. Ideally it allows easy follow up questions. Example could be this:

What length is and ipv4 address ?

The example of not-so-good question for phone interview:

How many usable hosts are in /23 subnet.

The main reason why this question is not very good is not it’s difficulty but the fact that it aims at the skill that is best presented in a whiteboard session as candidate can actually show you the binary translation and could elaborate how masks work and so on. Also in this time and age calculating subnets from top of your head seems bit unnecessary.

Then there is third type of question I call “prometric” or “cisco” style questions. These appear with incredible regularity and are very popular. But in most cases they are contentious or just plain bad.

What command would you use for ...

This first example is in my opinion just plain stupid as literally any cli has context help with the “?” so you really just need to understand the hierarchy and the bits that bind the requested function together. Also most the syntax can change between platforms and software streams so there is no point except for showing the capability of memorizing certain character string patterns. Much better question would be some simple scenario like what steps you need to take to enable function X.

What port would you open on firewall in order to allow IPsec traffic to pass through?

This question is seemingly straight forward as most people would just answer UDP/500. But this is not really how firewall works – you need to define the protocol, source, destination, security zones etc. Then your firewall must allow IKE/IPSEC pass-through which is something it might not be even capable of (looking at you screenos!) So yet again this question gives you no depth and only tells you that the candidate memorized a specific number.

As you can see in the examples above these “prometric” or “cisco” type questions are often trying to catch the candidate out on wording or with an abnormal /oversimplified situation. Extensive use of these questions has a dubious value as they tend to test the “exam technique” rather than knowledge and in my opinion it leads to serious disadvantage to people who are not familiar with ways of the certification world.

Some real-life examples of how not to interview

At the end of this article I would like to share some pearls that I’ve seen on interviews throughout my career from both both sides. These are the most memorable quotes and situations. Disclaimer: not all of them happened directly to me but most of them did some long time ago and some more recently.

  • Int he middle of discussion with HR about pay and benefits package at a large Chinese company 
Interviewer (HR): Hmm my husband is a CCIE so I know all about networking!
  • What not so say during a technical interview:
Interviewer: So what was a biggest professional challenge for you recently?	 	 
Candidate: To get on this interview...
  • Extremely overqualified person being interviewed by much less knowledgeable interviewer:
Interviewer: So can you describe a bridge?	 	 
Candidate: Yes sure - it is a construction that spans between two end-points allowing traffic across - like cars.
  • Candidate fresh form university with CCNA certification:
Interviewer: How would you describe an IP address.	 	 
Candidate: To see the IP address you click on the start menu - then networking...
  • Sent CV had somehow had a background set to blue – which in Black and white print resulted in unreadable grey pages
  • CV had couple of files attached inside the original word document.. unfortunately the CV had been converted to PDF somewhere along the way
  • CV was 16 pages long

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