Today I am an INTJ — Introverted Intuitive Thinking Judging. However, if you asked me a month ago, I was an INFJ — Introverted Intuitive Feeling Judging. One letter does not seem like a huge difference, but when it comes to psychometrics, or psychological testing, reliability is everything.
For those of you who may be confused by this seemingly arbitrary string of letters, I am talking about the Myers-Briggs Type Indicator. This widely used personality inventory was created by a mother-daughter team, comprising mother Katharine Briggs and daughter Isabel Briggs Myers, inspired by psychologist Carl Jung’s principles of cognitive functioning. They proposed 16 different personality types based on introversion and extroversion, sensing and intuition, thinking and feeling, and judgment and perception. It has gained popularity as a tool for job placement and counseling.
Contrary to its increased use and admiration, the MBTI produces questionable results. First, it is self-reported. It is incredibly easy for someone to fake the results he or she wants or the results he or she thinks are socially desirable. You want to be an extrovert? It is simple to find the questions related to extroversion and answer accordingly. Other personality tests have validity measures to prevent this type of biased response. Myers-Briggs does not.
Second, it is unreliable. The test does not produce the same results over time. A study at Marshall University reported that retesting after a five-week period yielded different results 50 percent of the time. Personality is supposed to be constant, but this seems to reflect a more flexible characteristic like mood or circumstance.
If nothing else, the main problem appears to be that the test proposes that personalities are dichotomous. You are introverted or you are extroverted. You are feeling or you are thinking. In reality, though, people lie on a spectrum. They do not fit neatly into categories and cannot be shoved into four letters.
Despite proof of its unreliability and thus invalidity, the MBTI is still widely used and trusted. CPP, the company that publishes the inventory, grosses close to $20 million annually on the test from over 10,000 companies, 2,500 colleges and 200 government agencies. That’s good marketing. Thousands of people are using it to choose their careers, create teams or enhance their resume.
I am not proposing a complete ban on the Myers-Briggs. I am advising against its use for decision making. Do you want to choose a career based on four letters that could change in a month? I did not think so. There are plenty of more reliable and valid psychological tools to help people find a career. The Myers-Briggs is the horoscope of personality tests. It is fun and can reflect how you see yourself, but it should not be used to make life choices.