The Myers-Briggs Type Indicator is one of the most widely used personality assessment instruments. It is a 100-question personality test. Respondents are classified as extraverted or introverted (E or I), sensing or intuitive (S or N), thinking or feeling (T or F), and judging or perceiving (J or P). Extraverted (E) versus Introverted (I). Extraverted individuals are outgoing, sociable, and assertive. Introverts are quiet and shy.

Sensing (S) versus Intuitive (N). Sensing types are practical and prefer routine and order, and they focus on details. Intuitives rely on unconscious processes and look at the big picture. Thinking (T) versus Feeling (F). Thinking types use reason and logic to handle problems. Feeling types rely on their personal values and emotions. Judging (J) versus Perceiving (P). Judging types want control and prefer order and structure. Perceiving types are flexible and spontaneous.

The MBTI is used by over 2.5 million people each year, and 89 of the Fortune 100 companies use it. Evidence is mixed about its validity as a measure of personality; however, most of the evidence is against it. One problem with the MBTI is that the model forces a person into one type or another; that is, you’re either introverted or extraverted. There is no in-between.

Another problem is with the reliability of the measure: When people retake the assessment, they often receive different results. The MBTI can thus be a valuable tool for increasing self-awareness and providing career guidance.