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Are personality tests useful for developers?

As a software developer my job is writing code. But knowing how to write code isn’t the only skill software developers need. We also need to have great teamwork skills, otherwise projects are doomed to fail.

Daniel Irvine · Sep 2, 2017 · teams career

As a software developer my job is writing code. But knowing how to write code isn’t the only skill software developers need. We also need to have great teamwork skills, otherwise projects are doomed to fail.

In my own work I’ve put a lot of effort into helping teams be happier and more successful, and I’m always on the lookout for extra tools to add to my toolbox.

Personality testing, like the Myers-Briggs Type Indicator, is one such tool. I had previously dismissed these tests as a gimmick: fun and interesting on an individual basis but not very useful and potentially dangerous in a business setting. However, I’ve changed my mind, and I’d like to tell you why.


Personality tests are a shortcut to building a deep understanding of your team. Long-term success for developers depends upon successful teamwork — a term that covers everything from communication to division of labor.

To explain why personality tests can help improve your teamwork skills, I’ll look at a couple of examples.

Introversion vs extroversion

One of the most basic ways to categorise personalities is introverts vs extroverts. I’m not much of a fan of labels as there’s a risk of assuming too much about people, but it is a useful model to help structure your thinking. For instance, take this statement, which you may or may not agree with: > Open-plan offices are terrible! I can’t get any work done with all this noise! We’re only suffering with open-plan because it’s cheaper than enclosed office rooms.

The trouble with this argument is that it’s wrong to assume that everyone or even the majority finds it difficult to work in open-plan offices just because you find it difficult.

In fact, some people will find the constant buzz a source of energy. This is the crux of the introversion/extroversion idea: some people gain energy from social interactions, and others lose energy. And there’s a whole lot of grey in between — for example, you may be energised by being around close friends but quickly drained by large crowds.

If that’s you, it doesn’t mean you dislike crowded environments — instead, you just have to limit your exposure. Perhaps you prefer short bursts rather than prolonged periods.

The two polar opposites of introversion and extroversion serves us a useful reminder that there’s no one dominant style of working that works best for everyone, and you can apply this thinking to your own office environment.

In our office we have two rooms — one is a ‘noisy’ room and one is a ‘quiet’ room. You’re free to choose which one you inhabit.

An exercise everyone should try is to think of all the social activities in your life that might drain or charge you. Then think about your colleagues and friends, and how their perspectives differ from your own.

For example, perhaps you attend local tech meetups. For some people these are energising, and for others they are very draining. I find them quite draining but also very useful and inspiring, so I do go to them but I tend to limit myself to one or two a month.

I also do quite a bit of public speaking, but that’s also quite draining. A more effective way for me to manage my energy is to write a blog post, where I can get my message out but remain fully charged.

If someone says to you “I’m an extrovert” and you’ve put in effort to understand what that might mean, then you should immediately know what kinds of social environments they’ll work well in and which they won’t. This is a key value of personality testing.

The many boxes of Myers-Briggs

Myers-Briggs Type Indicator is the most well-known personality test. Many think that it’s not all that useful in a business setting, but it’s worth studying to understand why. The type indicator part of the name comes from the fact that it categorises people into one of sixteen boxes and each has an encoded name that tells you about that type. For example, ENFP is a type. Every type indicator has four letters, for the four different dimensions that it cares about. I’m not going to discuss these in detail but we’ve already discussed the first dimension: a Myers-Briggs type starts with either an ‘E’ for ‘extrovert’ or an ‘I’ for introvert. The next three letters also have two possibilities each, which results in the sixteen boxes.

Assuming you know yourself well enough and can honestly assess yourself, it’s relatively easy to find out what your type indicator is by using online resources.

However, sixteen types is a lot. In fact it’s probably overkill if all you’re trying to do is figure out how to make your team run effectively. In my workplace we’ve used a more minimal alternative called DISC assessment.


The four letters stand for dominance, influence, steadiness, and compliance. This system gives a score to each of these dimensions relative to each other. So one person might be strong in one of the dimensions, and weak in the rest, or strong in two and weak in two.

What I found interesting about this system was that, for my team, one profile appeared again and again. In fact almost all of the team had a very similar profile — a combination of ‘S’ (steadiness) and ‘C’ (compliant). Only a a minority of the team deviated from that pattern.

My immediate reaction was to question how had this happened? How had we built a team that was all so similar? Presumably this isn’t indicative of a normal population, so perhaps it was a result of bias during hiring.

Since our team is made up of developers who care about code quality, and we follow well-formulated practices like TDD and merciless refactoring, it’s feasible that many of us are ‘rule-followers’ not just in our code writing but also in life. So we would naturally align with the ‘S’ and ‘C’ of DISC.

Personalities and hiring

Is it a problem if everyone on a team has a similar personality? Should we be aiming for a team with diverse personalities as we do with experience and background? And should we hire based on personality tests?

I’d argue that making applicants take personality tests is a step too far. It’s quite invasive, it’s not accurate, and it can be gamed since it’s based on self-assessment. Plus, people change over time, so I’d really question if there’s any value in this at all.

Personality testing has value for established, trusting teams because they won’t feel pressure to game the system.

In the case of my team, the exercise was useful not because we started hiring different people, but because some of the team who had measured as being ‘compliant’ suddenly realised that there was gap in our team, and that meant an opportunity to grow to be someone else — perhaps someone ‘dominant’ or maybe someone ‘influential’.

If our team retook the test now — more than a year later — I’d not be surprised if we had more variety in our results.

Empowered teams

In a traditional workplace environment a manager might have employee personalities measured in an effort to better orchestrate their team. Individual test results would be kept confidential between manager and employee, and there would be no team discussion. In this situation the only person who really benefits is the manager.

In self-managing teams, understanding one another’s personalities is empowering. The point is that personality tests are somewhat useful in isolation, but many times more useful if they are done as a team exercise, with the results shared and analysed amongst the whole team. In the same way a manager becomes more effective by understanding their employees, an entire team becomes more effective by understanding each other.

How to apply this on your team

Our team used a few hours on a Friday afternoon to take the test together, and then we analysed the results as a group. I would recommend this approach since it can generate a lot of insight about your team in a very short space of time, and you can do it yourselves using online tests. You could even do it in place of a standard team retrospective.

Another tool for the toolbox

As I said at the beginning of this post, personality testing is just another tool you can add to your toolbox. There are serious questions about the accuracy and reliability of these tests, especially if they are used for hiring. In addition, people’s personalities change as much as anything else in life, so profiling can only ever measure a snapshot in time.

That doesn’t, however, mean that personality testing can’t be useful to you and your team, as I hope I’ve demonstrated. If you’ve been cynical before then perhaps it’s worth another look.