Harvard Study Indicates Personality Screening Assessments are Fundamentally Flawed

Use assessment tests to screen the interviewers for bias not the candidates for competency.

As most of you know I’m a fan of Harvard professor Todd Rose and his new book, The End of Average. In the book Rose proves that many of the current hiring processes used by most companies are based on flawed science. According to Rose, personality-based assessment tests are part of the problem, certainly not a solution.

In his book, Rose endorses Performance-based Hiring and during our discussions before his book was published he asked me how I developed the process. While I’m not sure I told him all of the following stories, I did speak quite disparagingly about assessment tests and my early concerns.

The first story was from long ago. A candidate I was interviewing proudly told me his greatest strength was that he was an ENTJ. In Myers-Briggs speak this is “Life’s Natural Leader,” also known as an Extroverted, Intuitive, Thinking and Judging personality style. Of course, when I asked him what the biggest project he naturally led was, the project chosen was modest at best. So while he was a natural leader, he wasn’t very good at it. I subsequently met an ISFP who led an impressive company turnaround. This Introverted, Sensing, Feeling, Perceiving “Artist” somehow got things done by understanding people and creating a positive future vision.


Here’s another story, but more personal. It happened almost 40 years ago, but highlights the fundamental flaws with assessment tests. When I took my first DISC assessment it revealed I was dominant and influencing but didn’t have the temperament needed to be a good analyst or engineer. The truth was I prefer to be dominant and influencing but I’m a far better analyst and engineer. For example, on my first intern project in an R&D lab I developed a complex mathematical model (on an IBM System 3 using Fortran) for controlling the turbulent airflow surrounding high speed rotating equipment under dynamic pressure changes. I thought this was an exciting project especially when I later heard the company was implementing the process at multiple manufacturing facilities.

On a broader scale, one of our early clients – a well-known fast food chain – benchmarked its top performing store managers (dozens of them) and discovered there was no correlation between their on-the-job performance and the results of their Myers-Briggs, DISC, Calipers or their Predictive Index scores. None. In fact, many of them wouldn’t have been hired if the tests were being used at the time. As a result they decided to not use any of these types of tests to screen candidates.

On a broader scale, for 20 years at my staffing firm we gave all our final candidates (close to one thousand people) similar assessment tests. On one level we used these to confirm our performance-based assessments but we went one step further. We actually tracked the subsequent performance of many of these people. Following is what we concluded and why we created the BEST Personality Test of All Time summarized in the video. The point was to demonstrate that any test that could be completed in 30 seconds shouldn’t be taken too seriously.

The Fatal Flaws with Using Personality Assessments for Pre-screening

  1. These types of personality assessments test for preferences, not competencies or motivating interests.
  2. These types of personality assessments ignore adaptability and growth over time. Aside from the fact that the best people can adapt their style to meet the needs of the situation, professor Rose discovered that the best people grow, mature and change over time. I’m sure everyone reading this knows this to be true not only about themselves but also about just about every person you work with.
  3. There are just too many false positives (weaker candidates being considered) and false negatives (good people being screened out) for the tests to have any practical value. For example, at a major client we met one low key and unassuming sales rep who conducted deeper discovery than the typical flashier people already in the company. He turned out to be their number one rep out of more than 500 people five years in a row because he worked the hardest.

Despite the fact the personality assessments shouldn’t be used for screening candidates, we do use the BEST test as part of our Performance-based Hiring interviewing programs for managers to demonstrate how to control interviewing mistakes due to bias. A person’s style does impact how he/she interviews candidates, so neutralizing this is a great way to increase objectivity. The point: Use these assessment tests to screen the interviewers for bias not the candidates for competency.

Screening out good people for the wrong reasons and hiring people just like you’ve always hired seems like a recipe for stagnation. I’ve always known this to be true. I’m glad Professor Rose has now proved it.