Why Personality Assessments Do More Harm Than Good

Wouldn’t it be great if there existed a magical tool that could peer into a person’s soul and tell you how well they’ll turn out if you hire or promote them?  That’s pretty much what the nearly one-third of companies who use personality assessments believe they’ve found.  But what if there are flaws in this magical tool?  What harm could companies be unknowingly inflicting on people by basing hiring or promotion decisions on flawed data?

The Real Danger of Personality Assessments

The real danger of personality assessments is not that they don’t work at all, the danger is that they work differently than advertised.

Virtually every personality assessment comes with a disclaimer that sounds like this “This assessment should not be used as the sole factor in making employment related decisions such as hiring and promotion.”  Instead, personality assessment makers suggest that employers should use personality assessments in addition to other screening methods. They explain that their assessment only provides “part of the picture” and the other screening methods will help fill in the gaps, like this:



That’s a really bad analogy because it implies that personality assessments give an accurate representation of part of the picture.  The reality is that personality assessments are more like a Picasso painting that provides the whole picture but a distorted version, like this:


Personality assessments over-emphasize some aspects of people’s personality and under-emphasize, misplace, or omit other aspects.  Personality assessments don’t provide an accurate depiction of part of a person’s personality, they provide a distorted, misleading version of the whole picture.

Personality assessments don’t provide an accurate depiction of part of a person’s personality, they provide a distorted, misleading version of the whole picture.

Here’s why.

Lack of Context

Personality assessments attempt to discover aspects of your personality such as:

  • Good communicator or poor communicator?
  • Introverted or extroverted?
  • Persistent in the face of adversity or give up quickly?
  • Thinks through problems logically or haphazardly?

The problem is, we could be (and often are) all of these things depending on the situation.  But an assessment can’t possibly determine how a person will behave in every given situation.

Take me for example.  I fit the introvert profile almost perfectly.  Put me in a social setting with lots of people and I become a wall flower.  But put me on stage with a microphone in front of lots of people and I’m in my element. Would a personality assessment account for that slightly different circumstance?  Not a chance. I’d be placed squarely in the introvert category and provided boilerplate personality descriptors based on that classification.

Here’s an example of how personality assessments, which can’t possibly grasp the full context of a person’s personality, can lead to potentially inaccurate, damaging conclusions.

Not very long ago I considered adding personality assessments to my service offering.  As part of my research, I decided to take an assessment from an assessment provider who advises boards of directors on executive recruiting decisions.  The results of the assessment indicated that I’m not very good at reading people and I therefore wasn’t suitable for an executive level position. That’s an interesting revelation given that I make my living by selling my services to rooms full of CEOs.  (Reading and responding appropriately to body language and subtle cues is an essential skill to being an effective presenter and facilitator.)  When I explained this to the assessor during the follow up interview, she refused to believe that I possessed the talent to read people.  She was so convinced of the validity of her assessment that she created a no-win scenario for me to respond to in order to ‘prove’ her assessment was right.

Imagine if I took that assessment BEFORE I had irrefutable evidence to the contrary?  I may have decided against pursuing my greatest career dream because an assessment told me I lacked a talent that is clearly one of my strengths.  Now imagine if an employer was making employment-related decisions, such as whether to hire or promote me, based on that assessment. Those types of false negatives that result from an assessment’s narrow view of a person’s personality have the potential to ruin lives.

Not Reliable

The same person who takes the same assessment six months apart will almost always answer the same questions differently.  For example, one month after you take the Myers-Briggs, one of the most widely-used personality assessments, you have a 50% chance of landing in a different personality category.  Although many assessments claim to have a higher reliability rate than the Myers-Briggs, no personality assessment is even close to 100% reliable.

When I mentioned this point to a friend of mine who administers a certain personality assessment, she acknowledged this fact and correctly observed that people change over time which will be reflected in their personality assessment scores.  So even if personality assessments could reliably predict future performance, the predictions would only be useful as long as the person doesn’t change.  Except, people do change.  And those with the greatest potential change the most.


Because the results of personality assessments can have a significant financial impact on people’s lives, they come with a built-in incentive to cheat, or game, the assessment.  Some personality assessments claim that they are “designed in ways that mitigate gaming.” “Mitigating” gaming, however, does not eliminate it.

In addition to overt attempts to manufacture better results on personality assessments, there is a more subtle, unconscious sort of gaming that is virtually impossible to avoid. Because we know it’s a personality assessment, and we know that the people making us take the assessment take the results seriously, this undoubtedly biases our responses.  Every time we go to choose an answer, we can’t help but think “What answer do they probably want to hear?  What answer will make me look the best?”

This is precisely why researchers keep the true purpose of their psychological studies hidden from their test subjects.  If the subjects knew the true purpose of the study they were participating in, it would undoubtedly bias their behaviour, and therefore, invalidate the results of the study.  I find it laughable that the makers of psychometric (personality) assessments almost always claim that their assessments are “scientifically proven”, and yet they fail to meet this most basic standard of scientific rigor.

We Don’t Know Ourselves

A study published in the Journal of Personality found that employees themselves are about the worst judge of their own personalities.  The study concluded that co-workers and even family members were better judges of an employee’s personality than the employee themselves. The study’s author, professor Brian Connelly of Toronto’s Rotman School of Management observed “If we’re basing all the responses on self-reports, which is the norm, rather than having somebody else giving them the feedback, then we may be handing people’s biased perceptions right back to them.”

Another problem with personality assessments is that we answer them based on our current situation and experience.  We can’t possibly know or even indicate our potential in an area where we have no experience.  When I was an HR professional, I only thought of myself as an HR professional, not as a business owner.  Had I taken a personality assessment when I was a director of HR to determine if I could ever own my own business and succeed in sales, I would have undoubtedly unconsciously biased my responses away from having any skill in sales.

Further clouding our own self-knowledge is the perception our boss has of us.  Our boss’s opinion of us is perhaps the most important opinion of all when it comes to our economic survival and our psychological well-being. If you happen to have a terrible boss, that is likely going to negatively impact your own self-perception and reflect negatively in the results of a personality assessment.

Confirmation Bias

The reason people believe that personality assessments ‘work’ is the same reason people think horoscopes work.  When we believe in the validity of some instrument that claims to give us insight into ourselves, we instinctively look for evidence to confirm that insight.

Psychology author and blogger Hanan Parvez performed an experiment to test the validity of horoscopes by reading the Leo horoscope to his sister who was Scorpio.  He then asked her how true she thought it was.  “To my astonishment, she told me that all of it was true and matched her current life perfectly. I then revealed to her that I was actually reading a Leo horoscope!”  Parvez refers to this common response to personality assessment results as the “That’s me!” syndrome.

A personality assessment will almost certainly reflect back some things we already know about ourselves which leads us to believe “This must be true.”  When the assessment provides “new” information we didn’t already know, human tendency is to look for confirming evidence instead of questioning the validity of that information.  That’s the confirmation bias at work, and that’s why people who take personality assessments are likely to think they work.  It’s tough to avoid the trap of thinking “If some of it’s true, then the whole thing must be true.”

No Magic Short-Cuts

To use personality assessments to exclude people for employment or promotion is not only unjust, it is unethical.  Would you use a coin toss to decide between one candidate or another for promotion? If this seems at all morally objectionable to you, why then is it less unethical to base decisions that dramatically impact other people’s lives on less than 100% valid data?

I hate to be the guy that tells you there’s no Santa Clause, but there is no magic short-cut to fair, transparent, performance assessment.


8 Responses

  1. It’s apparent that you feel passionate about this topic because I think this is the longest blog you have written. I’m looking forward to your follow up blog about other tools to use that are more reliable or should I say maybe in addition to assessment tools. Having used a very extensive assement tool in my former role as HR manager for a national company I do agree that have their limitations. Even the moods the person is in the day they take the assessment will have some bearing on the outcome.

  2. Thank you very much for this wise article. In my previous career I was a computer scientist. At a certain stage I felt this career wasn’t satisfying for me. Throughout the year I researched what could be good for me, slowly gravitating towards people-focused careers. This was a hard enough process by itself, but then I took a career counseling service that included personality tests and a talk with a psychologist. To my dismay the tests showed that the career that would fit me perfectly would be…computer scientist!

    I was very disappointed that the test missed my potential for people-related work and told this to the psychologist, but to no avail. He did not understand nor support me in any way. I left the building in tears. It took me a long time to overcome this setback and return to pursue my quest to discover and embrace my true calling.

    Later on I choose Life Coaching as my new career. It has been 15 years since then. I enjoy every minute of my work and it does not feel as “work” at all. I excel at it have helped hundreds of people to truly improve their lives. I’m a very appreciated professional in my country and have been one of the founders of the Coaching Chamber, which promotes the highest standards of ethics and professionalism in Coaching.

    I absolutely relate to what was explained in this article and encourage people not let personality tests prevent them from being their real self and achieving what they aim to and rightfully deserve in life.

    1. Gabi – thank you so much for sharing your story. I can relate. Once the administrator of a test receives the results of the personality test, it seems that nothing can convince them that the test isn’t accurate.

      Well done on forging ahead despite this setback and finding work that you enjoy and which aligns with the strengths that your personality test overlooked.

  3. Thank you for attempting to shed light on these tests. I encountered the, first when applying for a job out of college. The test indicated I was a perfect choice for my specific field/career choice but apparently it also noted I was unstable and un-suited for work, they even had a phycologist on stand by to speak with me in a different room incase I “went off”.

    Now after being in Logistics for over 20 years, and a manager for 14 I recently needed to take these tests again for a job I was in the running for. Again the test indicated I was unstable and the IQ portion indicated that I was only fit for the most boring, repetitive, low end positions where no thinking or decision making was required.

    I refuse to fake the tests and in the past I curled up in bed and decided I was useless, then fought hard to come back. I have studied hard in many different areas of business and had been sought for advice and direction by many people.

    I ask why is it that these tests are still holding so much weight, you would think that experience, education and length of time in any position would mean something, but it does not.

    1. Thank you Caroline for adding your story to this article as another example of the harm that is often done by personality assessments.

  4. I just had one of these done and it cost me over $4k to get answers that I had been looking for my whole life. My diagnosis is complicated and it has a lot of moving parts–so after 30 years of no clear answer from self-proclaimed mental health professionals, I turned to this last resort. I got some answers and a lot of something else.

    That lump sum did not even get me each of the doctors who signed off reading it before they handed it to me; they told me its contents would be something other than what it turned out to be. Two weeks after pounding the drum, the lead doctor finally apologized and agreed to read the whole thing. They were inclined to be dismissive after multiple mentions of me be “delusional”. Heck of a way to preemptively discredit someone, and something no doctor in my extensive medical history would agree with.

    I guess the tipping point was in realizing that one of her underlings spat out 20 pages of completely contradictory information to the summary that was written by her. Like dude, I am in total disbelief–not just about the false statements that were made and used to make invalid points, but try explaining to these people what dealing in bad faith means or getting any accountability, glacially slow process.

    I still cannot condemn or invalidate the entire process that is one of these assessments. They can potentially uncover things that everyone else has missed, or provide clueless doctors with some actual clues. But if anything taking one of these assessments in and of itself is a slippery slope.

    1. Thank you for sharing your experience here. I am sorry to hear about the challenges you had with the process. I wish you the best of luck in your search for help with your mental health.

  5. I had to undergo a psychological evaluation many years ago. I understand the scope here is referring to personality assessments, whereas this exam is more inclusive of other tests and tactics. Regardless, I remember answering the questions in the oddest way as a youngster. It wasn’t that I was lying, but I was answering in a way that highlighted what I thought others thought of me. Thankfully I didn’t answer to what I really thought of myself at that time, because I was in an abusive situation with an ex-partner. I was also enduring the chronic and residual effects of childhood abuse and neglect due to a borderline mother with a drug addiction. Hindsight, the results of that exam really hindered my ability to get out of the abuse I was experiencing for quite some time. I had already felt ashamed for being abused, just as my mother had when she was 17 years old, so reading that I was delusional and paranoid justified my perceived incompetence that my ex-partner and mother eagerly proclaimed over the years prior. Eventually, I decided to go to school and become a nurse. From there I gained knowledge, skills, and financial freedom and shed the shame of trauma work. The psychology program I am in now teaches on the use of assessments, and it fairs similar to that of what I learned from nursing. Symptoms, complaints, and experiences are pieces to the puzzle rather than the entire picture. It takes time and various methods and assessments to fully grasp what is going on with an individual, let alone determine one’s personality that is shaped from experiences dating back to their development in the womb. So essentially, this article really resonates with me, and I am here to exclaim the dangers that personality tests can pose for any of us.

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