Thoughts on interviewing technical candidates and running technical tests

(We’re hiring – Drop us a line if you’d like to come and try our technical test!)

We’ve been expanding quite a lot recently, which is a good thing of course, but also means that you often need to spend a fair amount of time doing recruitment and interviews. I find this side of the business extremely interesting, and it’s something I’ve always enjoyed being involved in throughout my career. There are many schools of thought surrounding this topic, but here are some points which I like to cover when I recruit technical people for support and operational roles.

I always try to do a technical test. This may sound like a given, but in my experience it’s not always the case. Technical tests mean different things to different people, but I like to do technical tests where candidates get the opportunity to demonstrate in a real situation that they know how to troubleshoot things. I’m only in the business of recruiting operational and support staff and I think that this is a very specific field but one that is hard to test people on specific skills for. Therefore I like to watch someone fix something that is broken. I have all my candidates for the role to do the same technical test as well, so that I can compare and contrast.

Normally I tend to do my interviews like this:

1. CV reading – if it’s more than 2 pages I get bored and you’re unlikely to get through. This is a huge topic all of its own, but I’ll just say this: listing out every programming language, tool, script engine and piece of software you have ever been in the same room as does not impress me.

2. first interview – 1 hour usually and can be done by phone if appropriate. Are you generally appropriate for the role?

3. second interview – technical test (see more below)

4. third interview – meet managers and other team members (this could actually be more than one meeting)

5. make an offer

I am extremely passionate about recruiting the right people first time, and there are really no short cuts in this process. You need to be prepared to invest the time up front or you’ll be paying it back for years with the wrong candidate on board. (I learnt this the painful way when having candidates imposed on me much earlier in my career in the early 90’s, and I resolved to do all I could to avoid this situation as soon as I reached a level of seniority where I was allowed to recruit for myself.)

There’s enough literature out there about the interviewing process as a whole, but here are some more thoughts on the technical test side of things.

I like my technical tests to follow this theme:

a) simple theory closed questions about the main technical topics – these questions should have fixed answers. I think of these as textbook questions. (which to me means that you can parrot learn them so I don’t actually hold the results in that high a regard) A typical example might be:

What does ACID mean in terms of RDBMS?

b) more complex open questions about techniques or principals involved in the job. This should give the candidate the opportunity to give a lengthy full answer demonstrating their full knowledge of the topic. For example I usually ask about 10 questions of the following nature:

A customer complains that their website is running slow. Explain how you would go about troubleshooting this problem.

c) a practical test  – sit the candidate down in front of a computer and get them to attempt to do something which replicates what their day to day job might be. This can be painful at first as you need to spend time on creating a reproducible scenario that you want repeated candidates to test on, but it tends to be time extremely well spent.

I was challenged this week by the thought of writing a new technical test for candidates to our windows team. The stuff I wrote is certainly not going to win any design awards as the web pages it’s based upon look like this




(don’t you wish all webpages were this clean Smile – all my web development looks like this by the way)



anyway I’m not interviewing for people writing HTML, CSS or equivalents, I’m looking for operational people who can sort out why when I click the above button my website doesn’t work (amongst many other things)

The roles we are looking to fill here currently require quite broad experience and you need be a “jack of all trades” within the windows world. At any time you might be asked to troubleshoot Windows OS, SQL Server, IIS, BizTalk or innumerable other components. We have deep specialists in all these areas of course who can help with the most serious escalated problems , but the TAM roles we are looking to fill at the moment are much broader and you often need a working knowledge of all the components your customers are running.

My point being that this was a slightly more difficult test to write than some I’d done before, as just how do you cover all of these areas? The answer is that you can’t really, so in the end I just tried to cover the basics and allow the candidate to prove that she knew her way around windows troubleshooting generally across some of the major components. I covered such topics as troubleshooting an IIS server which wouldn’t serve a page correctly in a .NET application, simple SQL Server administrative tasks, windows ACLs and so forth.

After all I’m looking for a candidate who displays the correct attitude to troubleshooting a problem, and who displays a logical and methodical approach to problems presented to them. Solving the actual problem within a short interview timescale is actually irrelevant (although obviously it doesn’t do any harm). The other good thing is that you get to watch people do the test and I find you can often infer a lot about someone’s overall approach to this situation, especially if get them to talk you through what they are thinking. It’s worth remembering that the test is a means to an end, and as such you could test someone on a completely separate piece of technology, just to see how they handle the troubleshooting process and being put on the spot as well.

So don’t be surprised if you come and interview for us and get given something to fix.


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