Why You Shouldn't Use a Distorting Mirror - About the Validity of Personality Tests
Imagine: you are standing in front of a mirror to get to know yourself better. But it is no ordinary mirror, it is one from the fair: a distorting mirror. Your legs look three meters long, your head a balloon, and your torso shrunk to the size of a dollhouse. You see something – but it is not who you really are.
Yet, based on the image that this special mirror has given you, you make important decisions; you adjust your clothing, your posture and perhaps even your behaviour. You are surprised by what the mirror shows you, but you do not believe that this mirror has given you a wrong, or at least distorted, image of yourself. The funny thing is - everyone around you uses the same distorting mirror. They believe in it and the exoticism appeals to everyone; for team development, for recruitment, for career discussions. The mirror can simply be used for everything. No one really questions anymore what the mirror really does, or what it is made for.
This sounds absurd. Yet this is what happens when we use personality tests that do not measure what they claim to measure, or what the user believes they measure.
The illusion of simplicity
Tests such as the MBTI, DISC and RealDrives are popular in organisations. They offer recognisable colour codes, clearly defined ‘types’ of people, and above all understandable, accessible language. But the question should not be whether they are easy to use and whether the message sounds good and clear. The question should be what is being measured? On what foundations is the test used and are they correct, in other words reliable and valid?
The MBTI, for example, was developed by two enthusiasts without any formal training in behavioural science. They based it on the work of Carl Jung. The MBTI lacks any scientific basis necessary for a thorough, robust assessment. The test has been reviewed and included in the COTANregister due to a lack of validity and predictive power. The previous comments also apply, to a large extent, to variants of DISC and RealDrives; recognisable and fascinating but scientifically shaky.
Why is that a problem?
When you use a measuring instrument that does not measure what it claims to measure, you create a false image. Just like a crooked measuring cup in the kitchen: if 100 ml is actually 80 ml, your cake will fail, no matter how well you follow the recipe. And if a test only shows something from the outside - or only reflects what someone puts into it - you as an assessor run the risk of making crucial errors in your judgment, communication or division of tasks.
After all, personality tests often form the basis for crucial decisions about talent, potential and possibilities for cooperation. Then you want to be sure that the tools you have used have been reliable and valid.
Why companies still opt for such tests
The appeal of simple personality models lies in the promise of quick clarity. They give people the feeling that they understand themselves (and others) better and provide topics for discussion, surprising or recognisable insights and sometimes even a sense of recognition. But that does not make them accurate or useful.
Companies often choose these tests out of habit, because ‘everyone does it’, or because they seem to deliver results quickly and are available cheaply or sometimes even for free on the internet. People underestimate the true complexity of measuring psychological characteristics, let alone identifying personality traits and forming opinions about them. Speed and ‘easy to understand’ is certainly not (always) a sign of quality.
The power of validated tools
A validated test is like a genuine mirror. It may show you things you would rather not see, but the image you get comes much closer to reality. It provides insight into the interconnections between personality traits and an expert who assesses the results can explain the underlying dynamics and patterns. Not only explain but also make well-founded statements about strengths, pitfalls, vulnerabilities and expected behaviour. Validated tests are:
- Reliable: you get consistent results when repeated.
- Valid: they actually measure what they say they measure.
- Ethically responsible: you base your decisions on well-founded insight.
Examples of such tests include Hogan, NEO-PI-R or the HEXACO, all three of which are solidly substantiated and recognised by scientific bodies.
In conclusion
Personal and team development are too important to leave to distorted mirrors. If you really want to know who you are dealing with - or who you are yourself - choose a method that gives a clear image and ask an expert to explain the research results. No distortions, no superficial considerations but a solid basis for growth and cooperation.
Invest in a real mirror. Because only then can you truly see, understand and develop.
At Dantes , we specialise in assessing behavioural risks in people in sensitive or responsible positions. We use validated tools such as Hogan – internationally recognised personality tests that have been developed to reliably predict risk behaviour, integrity, leadership style and work behaviour.
Whether it concerns leadership development, team composition or screening candidates in critical positions; our approach is evidence-based, substantiated and aimed at preventing mistakes before they occur.
Would you like to know how we use screening and behavioural analysis within organisations? Feel free to contact us – if you would like to discuss this topic or learn more about our expertise and other options to support you or your organisation.
Inge Nijenhuis
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