Why You Shouldn’t Use Personality Tests for Sales Hiring

by Wendy Mack /

A few months ago, a former colleague of mine posted a LinkedIn update about how she uses the Myers-Briggs Type Indicator (MBTI) in career counseling.  I replied with a comment about having done almost every job that ENFJs are typically attracted to.  Little did I realize that one comment would set off a firestorm of comments.  People messaged me saying “Do you really believe in those things?” and “How could you endorse a personality test?”


Here’s the deal. I do believe personality tests can be useful and I don’t believe personality tests should be used for hiring. Here’s why.


For thousands of years, philosophers, scholars, and other observers of human behavior have noticed that there are patterns of differences in how people interact with the world around them. Personality is simply a term used to describe these patterns.  For decades, psychologists have been creating tests, indicators, and assessments that are intended to measure and describe personality.


Today, the personality assessment industry is thriving.  There are dozens of personality tests on the market.  MBTI, DISC, Birkman, Kolbe, Social Styles.  According to one source, the MBTI alone generates $20 million per year in revenue.  I’m willing to wager that if you ever participated in a teambuilding workshop, attended communication skills training, or worked with an executive coach, you have taken a personality test.


Personality tests are easily available and often inexpensive.  Some personality tests are even free.  Many people who take a personality test find the results interesting and insightful.  Most people even say that learning about their teammates’ personality is fun.


The problem is that that all the things that make personality tests popular have caused leaders and talent practitioners to make the jump to assuming that they can be useful tools for hiring.  After all, finding people whose personalities fit with certain jobs and company cultures is the holy grail of hiring – isn’t it?


So why shouldn’t you use personality tests for sales hiring decisions?


Personality tests don’t predict job performance.


For as long as people have been developing personality tests, there have been researchers proving the fact that these tests are simply not valid for hiring.  (For an in-depth review of the research, see our paper, The Problem with Personality Tests.)  The main challenges to validity include:

  1. Personality tests results aren’t reliable.
  2. Personality tests are easily manipulated or gamed.
  3. Most assumptions about what aspects of personality matter for job success are wrong.




Which Assessments Can Help You Make Better Sales Hiring Decisions?


Once they understand the downsides of personality tests, some people come to the blanket conclusion that any assessment that measures individual differences is bad.  Unfortunately, this point of view can prevent companies from benefitting from tools that have been proven to improve hiring.


The right assessments can and do help with hiring decisions. In fact, a 2018 study by the Brandon Hall research firm found that, “Organizations using pre-hire assessments are more likely to see year-over-year improvement in quality of hire (44% vs. 32%) and employee retention (32% vs. 23%) than their cohorts.”  Pre-hire assessments also help to improve the quality of interviews by helping managers know where to probe and by accelerating the onboarding of new hires into the organization.


Predictive assessments (such as GrowthPlay’s own Chally Assessment™) gauge a seller’s disposition and potential to perform the tasks required of specific sales roles.  When used appropriately, these assessments can reliably and accurately predict whether a person’s inherent strengths align with the competencies or attributes that have been shown to correlate with success in that role.  Like the way a DNA strand identifies the genetic makeup of an individual, predictive assessments give us a way to measure attributes that are not always apparent on the surface and that can’t be gauged through interviews and observation.


Predictive Assessments vs Personality Tests


The lesson here is not to lump all assessments into one category.  In order to make better sales hires, look for predictive assessments – not personality tests.  Here is a simple way to distinguish between the two types of assessments.

  • Personality tests are designed to describe an individual based on a theory of personality.
  • Predictive hiring assessments are designed to predict on-the-job behaviors, outcomes, or criteria important to work-related performance.


People’s passions around personality tests tend to swing to one extreme or the other.  Some say they are pointless, and others overestimate their value.  In my opinion, the problem is not with the construct of personality. The problem is using any test for applications for which it is not valid.  It’s okay to use personality tests for self-awareness, communication skills, and career coaching.  Just be sure you are using predictive assessments for hiring.


Read more: The Problem with Personality Tests

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