According to the Myers & Briggs Foundation, the MBTI meets accepted standards of reliability and validity. However, other studies have found that the reliability and validity of the instrument have not been adequately demonstrated.
Studies have found between 40% and 75% of respondents receive a different result after completing the inventory a second time.
A 1992 book by The Committee on Techniques for the Enhancement of Human Performance and the National Research Council suggests that "there is not sufficient, well-designed research to justify the use of MBTI in career counseling programs. Much of the current evidence is based on inadequate methodologies."