A mother-daughter team with no psychology degrees created the world's most used personality test.
The Myers-Briggs Type Indicator, the most widely administered personality test in the world, was created by Katharine Cook Briggs and her daughter Isabel Briggs Myers. Neither held a degree in psychology. Katharine Briggs became interested in personality typology after reading Carl Jung's Psychological Types in 1923, and she spent two decades developing a questionnaire based on Jung's framework.1
Isabel Briggs Myers brought the project to fruition during World War II, motivated by the belief that understanding personality types could help women entering the workforce for the first time find jobs suited to their temperaments. The first version of the indicator was published in 1943.2 Educational Testing Service distributed it from 1957, and Consulting Psychologists Press took over in 1975.
Employers adopted personality testing enthusiastically. By the twenty-first century, an estimated 50 million people take the Myers-Briggs assessment annually, and 88 of the Fortune 100 companies have used it in some capacity.3
The scientific consensus on the MBTI is largely critical. A review in the Journal of Career Planning and Employment found that roughly 50 percent of test-takers receive a different type classification when retaking the assessment five weeks later.4 The National Academy of Sciences concluded in 1991 that there was insufficient evidence to justify the use of the MBTI in career counseling programs.5 Employers continue to use it.