What Personality Tests Really Reveal

There are a lot of personality tests claiming to tell you how to work best. Here’s how to make sense of them all.

What Personality Tests Really Reveal
[Photo: Flickr user Rachel Sapp]

Because the human mind is such a mystery, we gravitate toward things that aim to give us insight into our minds and the minds of others. This is why personality tests are so appealing. With a relatively small number of questions, these tests provide feedback that (we hope) predicts behavior in future situations.


Of course, just because people answer a set of questions (even if those questions sound scientific), that doesn’t mean that those questions are going to do a good job of predicting their actions.

Most of the questionnaires given in the workplace address aspects of personality. Some of them aim to highlight core elements of personality. Others aggregate traits together to try to predict who will succeed at particular workplace tasks like leadership or creative thinking.

If you are considering using personality tests for yourself or the people you work with, it is important to know a little more about personality, so that you can pick a questionnaire that will actually be useful.


The Limits Of Personality

Personality is a broad name for reasonable stable differences between people in they way they act and react in particular situations. Personality differences reflect the settings of your motivational system—the set of brain mechanisms that drive your behavior. Each person has a motivational system that is tuned slightly differently to the world.

People’s behavior always reflects an interaction between that person’s motivational characteristics and the situation they are in. Sometimes, the situation strongly governs behavior. Even someone who hates following rules will stand in line in a government office when filing paperwork. Other times, the situation does not constrain people’s behavior much, and so personality plays a greater role. At a social gathering, people who enjoy being the center of attention can engage a group of people in spirited conversation, while those who are uncomfortable in crowds can hang near the edge.

The Three Characteristics Of Best Personality Tests


1.They have been validated with studies. It is easy to throw together an inventory that aims to address elements of personality. This is the staple of the magazines you see at the supermarket checkout lane. If you are going to use surveys in the workplace, though, you want to know that differences in the scores people get on the survey are reliably related to differences in behavior.

2. They measure aspects of personality. This may seem like a strange thing to say, but remember that personality reflects settings of the motivational system. For example, people differ in their “Openness to Experience.” This characteristic reflects the degree to which people are motivated to consider or pursue new ideas, people, or opportunities.


Aptitude for particular tasks is not really a personality characteristic. Leadership potential is not a personality characteristic. Creativity is not a personality characteristic. There are aspects of motivation that can make someone more or less likely to be a good leader or creative, but assessing that requires one step of determining a set of underlying personality characteristics and a second step of comparing those characteristics against criteria that would make someone succeed at a task (like leadership or creativity).

3. They have good test-retest reliability. That is, if you give the test to the same person several times, you should get substantially the same results. Personality reflects long-term stabilities in people’s behavior, and not the particular reaction someone may have to a specific situation.


Given these three aspects of good personality inventories, there are several things you can do to assess whether a particular survey is right for you and your company.

Check The Research

There is a lot of excellent personality research that goes back 50 years. Some personality inventories have been used in a large number of studies successfully. Personality psychologists have identified five core personality characteristics (helpfully called the Big Five). Inventories that measure the Big Five are a great first step in understanding personality differences in people at work. There are also excellent inventories for other, more specialized characteristics that might influence people’s behavior at work.

Myers-Briggs Type Indicator. In this context, it is worthwhile saying a couple of words about the Myers-Briggs Type Indicator (MBTI). The MBTI has been used extensively by consultants. More than once, I have walked into workplaces where people have badges indicating their personality types as assessed by the MBTI.


Unfortunately, the MBTI has not fared well in scientific studies. There are many problems with the MBTI, but perhaps the most glaring is that it is used to categorize people along four dimensions. Studies of personality suggest that most of the population is around the middle of the distribution on most personality characteristics. That means that most of us have elements of both poles of a personality dimension in our psychology. So, an inventory that categorizes people is likely to make you think people are more extreme in their characteristics than they really are.

In general, I won’t make many other specific recommendations for or against particular inventories. However, I do recommend staying away from the MBTI. If you are trying to measure the basic personality dimensions, then use an inventory for the Big Five characteristics.The Big Five personality traits, also known as the five factor model (FFM), is a widely examined theory of five broad dimensions that psychologists use describe personality.

The Big Five are:

  1. Openness to Experience
  2. Conscientiousness
  3. Extraversion
  4. Agreeableness
  5. Neuroticism

Separate Personality From Aptitude

Many companies offer assessments that suggest directly whether particular people are likely to succeed at specific tasks. To use the examples I gave earlier, a survey might assess a person’s leadership potential or their likelihood of being creative.


If you are going to use an inventory like this in your workplace, it is important to ensure that you have access both to the assessment of personality characteristics and the assessment of people’s potential. There are two reasons for wanting this breakdown. First, assessment of potential is an inference that goes beyond just assessment of the personality characteristics, and so you would like to have the more basic measurements available for your use. Second, there are many factors that may make someone relatively fit for a position. It would be useful to have information about a person’s characteristics, and not just his or her potential to succeed.

Many companies will provide you with both the assessments of aptitude and the measures of the underlying characteristics on which those assessments are based.

The bottom line is that there can be a lot of value in using personality assessments in the workplace. However, it is crucial to do your homework before committing to any one in particular.