Some grandmothers pass down cameo necklaces. Katharine Cook Briggs passed down the world’s most widely used personality test.

Chances are you’ve taken the Myers-Briggs Type Indicator, or will. Roughly 2 million people a year do. It has become the gold standard of psychological assessments, used in businesses, government agencies and educational institutions. Along the way, it has spawned a multimillion-dollar business around its simple concept that everyone fits one of 16 personality types.

Now, 50 years after the first time anyone paid money for the test, the Myers-Briggs legacy is reaching the end of the family line. The youngest heirs don’t want it. And it’s not clear whether organizations should, either.

That’s not to say it hasn’t had a major influence.

More than 10,000 companies, 2,500 colleges and universities and 200 government agencies in the United States use the test. From the State Department to McKinsey Co., it’s a rite of passage. It’s estimated that 50 million people have taken the Myers-Briggs personality test since the Educational Testing Service first added the research to its portfolio in 1962.

The test, whose first research guinea pigs were George Washington University students, has seen financial success commensurate to this cultlike devotion among its practitioners. CPP, the private company that publishes Myers-Briggs, brings in roughly $20 million a year from it and the 800 other products, such as coaching guides, that it has spawned.

Yet despite its widespread use and vast financial success, and although it was derived from the work of Carl Jung, one of the most famous psychologists of the 20th century, the test is highly questioned by the scientific community.

To begin even before its arrival in Washington, D.C.: Myers-Briggs traces its history to 1921, when Jung, a Swiss psychiatrist, published his theory of personality types in the book “Psychologische Typen.” Jung had become well known for his pioneering work in psychoanalysis and close collaboration with Sigmund Freud, though by the 1920s the two had severed ties.

Katharine Cook Briggs, a mother in D.C., was a voracious reader of the new psychology books coming out in Europe, and she shared her fascination with Jung’s latest work — in which he developed the concepts of introversion and extraversion — with her daughter, Isabel Myers. They would later use Jung’s work as a basis for their own theory, which would become the Myers-Briggs Type Indicator (MBTI).

MBTI is their framework for classifying personality types along four distinct axes: introversion vs. extraversion, sensing vs. intuition, thinking vs. feeling and judging vs. perceiving. A person, according to their hypothesis, has one dominant preference in each of the four pairs. For example, he might be introverted, a sensor, a thinker and a perceiver. Or, in Myers-Briggs shorthand, an “ISTP.”

Everyone, they posited, fits one of the 16 possible combinations.

Today, organizations administer the personality test to employees, then use the results as a basis for training programs. The basic idea is that knowing your personality type, and those of others, will help you interact more effectively with colleagues and better identify your own strengths. In educational institutions, the test is often used to help identify potential career fields.

The testing process seems simple enough: a multiple-choice questionnaire, with a discussion afterward about what your personality type says about you. And yet behind it lies the elaborate business model and enormous marketing push that have enthroned MBTI in the pantheon of human-resources programs.

Corporate America has its own religions, and one of them is Myers-Briggs.

Identifying proclivities

World War II created a need for women to fill professional jobs on the home front. Having read Jung’s theories on type, Isabel Myers saw an opportunity to use personality testing as a way to identify women’s job proclivities on the basis of innate character traits rather than previous professional experience, which many women did not have at the time.

“What Isabel decided was, if she could give people access to knowing their psychological type, it would be a contribution to world peace,” says Katharine Myers, the daughter-in-law of Isabel Myers.

So Isabel had her mission. Soon her home filled with index cards mapping out her theory. Lots of index cards.

Isabel by that time was married, a mother herself and tending a home in Swarthmore, Pa. She found a helper for her project in Katharine Downing, now Myers, whom she paid to help her hand-copy personality types onto 5-by-8-inch cards. The young girl went to school with Isabel’s son Peter, an Eagle Scout.

At 86 years old, Katharine and Peter are the last living copyright holders of his mother’s and grandmother’s legacy. CPP, however, is the exclusive publisher of the test.

“The folklore is that when it started it made about a thousand dollars,” says Jeffrey Hayes, chief executive of CPP, which is headquartered in Mountain View, Calif. He won’t say precisely how much it makes today. Just “millions,” as he put it.

The number is more like $20 million in revenue a year.

The framework itself has barely changed since Katharine Cook Myers and Isabel Briggs created it decades ago.

The business model

MBTI is the most widely used personality assessment on the planet, but as Hayes says, “There’s a lot that goes on behind the scenes to make that happen.”

Here’s how the business model works: It costs $15 to $40 for an individual to take a Myers-Briggs assessment, depending on the depth of the test and how fast a customer wants the results interpreted. Supplemental guides and tool kits quickly make the cost grow. Moreover, the only way to take the test is through a certified administrator. And the only way to become a certified administrator is to pay $1,700 for a four-day training class.

In short, CPP makes money off the test taker and the test giver.

Organizations administer the MBTI assessment to employees in one of two ways. They either pay for someone in their human-resources department to become certified, then pay the materials costs each time employees take the test. Or, they contract with certified, independent training consultants or leadership coaches.

Last year 2,500 Americans became certified to administer the Myers-Briggs.

As a result, CPP has combined the power of its own marketing efforts and its roughly 200 employees with the sales efforts of the thousands of professional-development coaches who pay CPP for certification and then essentially sell the test on the publishing company’s behalf.

“We get a percentage of the sales,” Katharine Downing Myers says of the copyright. “I have more money than I expected to have in life.”

Isabel Myers would turn out, by her own rubric, to be an INFP — an introvert, an intuitor, a feeler and a perceiver. She would also turn out to be obsessive about the indicator.

It would take roughly two decades for her work to make it from the stacks of index cards to the research holdings of the Educational Testing Service in the early 1960s. In the interim, she had looked for more opportunities to legitimize her homegrown project.

“That was her mission in life,” Katharine Downing Myers recalls, “and she worked on it early in the morning until she went to bed at night.”

Starting in 1945, Isabel administered tests to more than 5,000 students, charted their personalities and then looked for correlations between their psychological type and the medical specializations they chose.

Initially the Educational Testing Service acquired Myers-Briggs for research use, not as part of its testing portfolio. So by 1975 Isabel struck a deal with Stanford professor John Black allowing his young publishing company, Consulting Psychologists Press (now CPP), to take over the exclusive publishing rights.

“Cultlike devotion”

The test then gained momentum in the marketplace, thanks to CPP’s aggressive marketing push. And yet, its living-room origins would cast a shadow over its scientific validity that remains today.

“What concerns me is the cultlike devotion of many consultants and practitioners to it without the examination of the evidence,” says Adam Grant, a professor of industrial psychology at the University of Pennsylvania’s Wharton School.

Despite the far-reaching use of the assessment in organizations, the academic psychological community has been slow to embrace it. No major journal has published research on the MBTI, which academics consider a strong repudiation of the test’s authority. What makes this even more striking is that CPP has three prominent psychologists on its corporate board.

Carl Thoresen, the CPP board’s chairman, is a longtime and highly regarded professor of psychology at Stanford. And yet of the roughly 150 papers he has published in his career, there isn’t one mention of Myers-Briggs.

He said he didn’t use it “because it would be questioned by my academic colleagues. That was always a barrier.”

But there are concrete reasons it was not welcomed in the first place.

“Carl Jung was a pioneer in terms of really creative and novel theory and ideas, but a lot of his work was done before psychology was an empirical science,” says Grant, the Wharton psychology professor.

And the 16 Myers-Briggs personality types, remember, are even a step removed from that — they are an interpretation and recasting of Jung’s theory. Even more compromising, according to Grant, is the fact that Katharine Cook Briggs and Isabel Myers created the framework in their living room before doing any robust scientific research.

Even Katharine Downing Myers concedes that “psychologists had no use for the indicator; they felt that Jung was a crazy mystic.”

CPP has plans to make a large research push over the next three or four years, which would amass millions of its cases and pull them into research that should be publishable by the top-tier psychological journals.

When the copyright passed to Katharine and Peter in 1980, after Isabel’s death, the pair became the vision keepers of her legacy. “We have been partners in really carrying out her dream,” Katharine says. “I think of it as protecting both the instrument and the theory on which it is based.”

Upon their death, the copyright will go to the Myers-Briggs Foundation, which funds research and helps maintain the nonprofit Center for Applications of Psychological Type.

When asked if he is sad his children won’t carry on the family legacy, Peter replies, “Yes, but that’s the luck of the draw.”