Myers-Briggs Type Indicator

The Myers-Briggs Type Indicator (MBTI) assessment is a psychometric questionnaire designed to identify certain psychological differences according to the typological theories of Carl Gustav Jung as published in his 1921 book Psychological Types (English edition, 1923). The original developers of the personality inventory were Katharine Cook Briggs and her daughter, Isabel Briggs Myers. They began creating the indicator during World War II, believing that a knowledge of personality preferences would help women who were entering the industrial workforce for the first time identify the sort of war-time jobs where they would be "most comfortable and effective". The initial questionnaire grew into the Myers-Briggs Type Indicator, which was first published in 1962. The MBTI focuses on normal populations and emphasizes the value of naturally occurring differences.

While some academic psychologists have criticized the MBTI instrument in research literature, claiming that it "lacks convincing validity data," proponents and sellers of the test cite unblinded anecdotal predictions of individual behaviour. Moreover, the indicator has been found to meet or exceed the reliability of other psychological instruments. For most adults (75-90%), though not for children, the MBTI gives the same result when the test is administered to the same person more than once. Studies have found strong support for construct validity, internal consistency, and test-retest reliability, although variation was observed.

The registered trademark rights to the terms Myers-Briggs Type Indicator and MBTI have been assigned from the publisher of the test, CPP, Inc., to the Myers-Briggs Type Indicator Trust.

The definitive published source of reference on the Myers-Briggs Type Indicator is The Manual produced by CPP, from which much of the information in this article is drawn, along with training materials from CPP and their European training partners, Oxford Psychologists Press. However, a popularized source of the model, with an original test, is published in David Keirsey's book Please Understand Me.

Concepts

Type

Fundamental to the Myers-Briggs Type Indicator is the concept of Psychological Type as originally developed by C. G. Jung.

The typology model originated by Jung (and further developed by Briggs and Myers) regards personality type as similar to left or right handedness: individuals are either born with, or develop, certain preferred ways of thinking and acting. The MBTI sorts some of these psychological differences into four opposite pairs, or "dichotomies," with a resulting 16 possible psychological types. None of these types is "better" or "worse"; however, Briggs and Myers recognized that everyone naturally prefers one overall combination of type differences. In the same way that writing with the left hand is hard work for a right-hander, so people tend to find using their opposite psychological preferences more difficult, even if they can become more proficient (and therefore behaviorally flexible) with practice and development.

The 16 different types are often referred to by an abbreviation of four letters, the initial letters of each of their four type preferences (except in the case of iNtuition), for instance:

• ESTJ - Extraversion, Sensing, Thinking, Judging
• INFP - Introversion, iNtuition, Feeling, Perceiving

And so on for all 16 possible type combinations.

The four dichotomies

Dichotomies
Extraversion	Introversion
Sensing	iNtuition
Thinking	Feeling
Judging	Perceiving

The four pairs of preferences or dichotomies are shown in the table to the right.

Note that the terms used for each dichotomy have specific technical meanings relating to the MBTI which differ from their everyday usage. For example, people with a preference for Judging over Perceiving are not necessarily more "judgmental" or less "perceptive".

Nor does the MBTI instrument measure aptitude; it simply indicates for one preference over another. Someone reporting a high score for Extraversion over Introversion cannot be correctly described as 'more' Extraverted: they simply have a clear preference.

Point scores on each of the dichotomies can vary considerably from person to person, even among those with the same type. However, Isabel Myers considered the direction of the preference (for example, E vs. I) to be more important than the degree of the preference (for example, very clear vs. slight).

Attitudes: Extraversion (E) / Introversion (I)

The preferences for Extraversion (thus spelled in Myers-Briggs jargon) and Introversion are sometimes referred to as attitudes. Briggs and Myers recognized that each of the functions can show in the external world of behaviour, action, people and things (extraverted attitude) or the internal world of ideas and reflection (introverted attitude). The Myers-Briggs Type Indicator sorts for an overall preference for one or the other of these.

People with a preference for Extraversion draw energy from action: they tend to act, then reflect, then act further. If they are inactive, their level of energy and motivation tends to decline. Conversely, those whose preference is Introversion become less energized as they act: they prefer to reflect, then act, then reflect again. People with Introversion preferences need time out to reflect in order to rebuild energy. The Introvert's flow is directed inward toward concepts and ideas and the Extravert's is directed outward towards people and objects. There are several contrasting characteristics between Extraverts and Introverts: Extraverts desire breadth and are action-oriented, while introverts seek depth and are thought-oriented.

The terms Extravert and Introvert are used in a special sense when discussing the Myers-Briggs Type Indicator.

Functions: Sensing (S) / iNtuition (N) and Thinking (T) / Feeling (F)

Jung identified two pairs of psychological functions: the two Perceiving functions, Sensing and iNtuition (thus spelled in Myers-Briggs jargon to distinguish it from Introversion); and the two Judging functions, Thinking and Feeling. Although each person uses one of these four functions more dominantly and proficiently than the other three, all four functions are used at different times depending on the circumstances.

Sensing and iNtuition are the information-gathering (Perceiving) functions. They describe how new information is understood and interpreted. Individuals who prefer Sensing are more likely to trust information that is in the present, tangible and concrete: that is, information that can be understood by the five senses. They tend to distrust hunches that seem to come out of nowhere. They prefer to look for details and facts. For them, the meaning is in the data. On the other hand, those who prefer iNtuition tend to trust information that is more abstract or theoretical, that can be associated with other information (either remembered or discovered by seeking a wider context or pattern). They may be more interested in future possibilities. They tend to trust those flashes of insight that seem to bubble up from the unconscious mind. The meaning is in how the data relates to the pattern or theory.

Thinking and Feeling are the decision-making (Judging) functions. The Thinking and Feeling functions are both used to make rational decisions, based on the data received from their information-gathering functions (Sensing or iNtuition). Those who prefer Feeling tend to come to decisions by associating or empathizing with the situation, looking at it 'from the inside' and weighing the situation to achieve, on balance, the greatest harmony, consensus and fit, considering the needs of the people involved. Those who prefer Thinking tend to decide things from a more detached standpoint, measuring the decision by what seems reasonable, logical, causal, consistent and matching a given set of rules.

As noted already, people with a Thinking preference do not necessarily, in the everyday sense, 'think better' than their Feeling counterparts; the opposite preference is considered an equally rational way of coming to decisions (and, in any case, the MBTI assessment is a measure of preference, not ability). Similarly, those with a Feeling preference do not necessarily have 'better' emotional reactions than their Thinking counterparts.

Dominant Function

Although people use all four cognitive functions, one function is generally used in a more conscious and confident way. This dominant function is supported by the secondary (auxiliary) function, and to a lesser degree the tertiary function. The fourth and least conscious function is always the opposite of the dominant function. Jung and Myers called this the inferior, or shadow, function.

The four functions operate in conjunction with the attitudes (Extraversion and Introversion). Each function is used in either an extraverted or introverted way. A person whose dominant function is extraverted intuition, for example, uses intuition very differently from someone whose dominant function is introverted intuition.

Lifestyle: Judging (J) / Perception (P)

Myers and Briggs added another dimension to Jung's typological model by identifying that people also have a preference for using either the Judging function (Thinking or Feeling) or their Perceiving function (Sensing or iNtuition) when relating to the outside world (extraversion).

Myers and Briggs taught that types with a preference for Judging show the world their preferred Judging function (Thinking or Feeling). So TJ types tend to appear to the world as logical, and FJ types as empathetic. According to Myers, Judging types prefer to "have matters settled." Those types ending in P show the world their preferred Perceiving function (Sensing or iNtuition). So SP types tend to appear to the world as concrete and NP types as abstract. According to Myers, Perceiving types prefer to "keep decisions open."

For Extraverts, the J or P indicates their dominant function; for Introverts, the J or P indicates their auxiliary function. Introverts tend to show their dominant function outwardly only in matters "important to their inner worlds". For example:

Because ENTJ types are Extraverts, the J indicates that their dominant function is their preferred Judging function (Extraverted Thinking). ENTJ types introvert their auxiliary Perceiving function (Introverted iNtuition). The tertiary function is Sensing and the inferior function is Introverted Feeling.

Because INTJ types are Introverts, the J indicates that their auxiliary function is their preferred Judging function (Extraverted Thinking). INTJ types introvert their dominant Perceiving function (Introverted iNtuition). The tertiary function is Feeling, and the inferior function is Extraverted Sensing.

Whole type

The expression of a person's psychological type is more than the sum of the four individual preferences, because of the way in which the preferences interact through type dynamics and type development (see below). Descriptions of each type can be found on the TypeLogic website. In-depth descriptions of each type, including statistics, can be found in The MBTI Manual (op cit).

Historical development

C. G. Jung first spoke about typology at the Munich Psychological Congress in 1913. Katharine Cook Briggs began her research into personality in 1917, developing a four-type framework: Social, Thoughtful, Executive, and Spontaneous. In 1923 Jung's Psychological Types was published in English translation (having first been published in German in 1921). Katharine Briggs' first publications are two articles describing Jung's theory, in the journal New Republic in 1926 (Meet Yourself Using the Personality Paint Box) and 1928 (Up From Barbarism). Katharine Briggs' daughter, Isabel Briggs Myers, wrote a prize-winning mystery novel Murder Yet to Come in 1929, using typological ideas. She added to her mother's typological research, which she would progressively take over entirely. In 1942, the "Briggs-Myers Type Indicator" was created, and the Briggs Myers Type Indicator Handbook was published in 1944. The indicator changed its name to the modern form (Myers-Briggs Type Indicator) in 1956.

Differences from Jung

The most notable addition to Jung's original thought by Myers and Briggs is their notion that a given type's fourth letter (J or P) is determined by how that types interacts with the outer external world, rather than how that type functions inwardly. The difference becomes evident when assessing the functions of Introverts.

To Jung, a type with dominant Introverted Thinking would be considered "rational" (Judging). To Myers, however, that same type would be inwardly rational, but "irrational" (Perceiving) when interacting with the outer world. Expressed in MBTI letters, this discrepandency would mean, for example, that a Jungian Introverted Thinker with iNtuition would be characterized as INTJ, while for Myers, the same type would be characterized as INTP. In the Myers INTJ, the perceiving function is dominant but used with the internal world:

Jung's INTJ

• Dominant: Introverted Thinking
• Auxiliary: Extraverted iNtuition

Myers' INTJ

• Dominant: Introverted iNtuition
• Auxiliary: Extraverted Thinking

Noted psychologist H.J. Eysenck calls the MBTI a moderately successful quantification of Jung's original principles as outlined in Psychological Types. Other continuations of Jungs typology, such as Socionics, have retained the original Jungian way of designating J and P.

Format and administration of the MBTI

The current North American English version of the MBTI Step I includes 93 forced-choice questions (there are 88 in the European English version). Forced-choice means that the individual has to choose only one of two possible answers to each question. The choices are a mixture of word pairs and short statements. Choices are not literal opposites but chosen to reflect opposite preferences on the same dichotomy. Participants may skip questions if they feel they are unable to choose.

Using psychometric techniques, such as item response theory, the MBTI will then be scored and will attempt to identify the preference, and clarity of preference, in each dichotomy. After taking the MBTI, participants are usually asked to complete a Best Fit exercise (see above) and then given a readout of their Reported Type, which will usually include a bar graph and number to show how clear they were about each preference when they completed the questionnaire.

During the early development of the MBTI thousands of items were used. Most were eventually discarded because they did not have high midpoint discrimination, meaning the results of that one item did not, on average, move an individual score away from the midpoint. Using only items with high midpoint discrimination allows the MBTI to have fewer items on it but still provide as much statistical information as other instruments with many more items with lower midpoint discrimination. The MBTI requires five points one way or another to indicate a clear preference.

Additional formats

Isabel Myers had noted that people of any given type shared differences as well as similarities, and at the time of her death was developing a more in depth method to offer clues about how each person expresses and experiences their type pattern, which is called MBTI Step II.

In addition to this, the Type Differentiation Indicator (TDI) (Saunders, 1989) is a scoring system for the longer MBTI, Form J , that includes the 20 subscales above, plus an additional factor of Comfort-Discomfort (which purportedly corresponds to the missing factor of Neuroticism), with seven additional scales indicating a sense of overall comfort and confidence versus discomfort and anxiety (guarded-optimistic, defiant-compliant, carefree-worried, decisive-ambivalent, intrepid-inhibited, leader-follower, proactive-distractible), plus a composite of these called "strain". Each of these comfort-discomfort subscales also loads on one of the four type dimensions, e.g., proactive-distractible is also a judging-perceiving subscale. There are also scales for type-scale consistency and comfort-scale consistency. Reliability of 23 of the 27 TDI subscales is greater than .50; "an acceptable result given the brevity of the subscales" (Saunders, 1989).

A "Step III" is also being developed in a joint project involving CPP, publisher of the whole family of MBTI works; CAPT (Centre for Applications of Psychological Type), which holds all of Myers' and McCaulley's original work; and the MBTI Trust, headed by Katharine and Peter Myers. Step III will further address the use of perception and judgment by respondents.

Precepts and ethics

The following precepts are generally used in the ethical administration of the Myers-Briggs Type Indicator:

Type not trait: The MBTI sorts for type; it does not indicate the strength of ability. The questionnaire allows the clarity of a preference to be ascertained (Bill clearly prefers introversion), but not the strength of preference (Jane strongly prefers extraversion) or degree of aptitude (Harry is good at thinking). In this sense, it differs from trait-based tools such as 16PF. Type preferences are polar opposites: a precept of MBTI is that you fundamentally prefer one thing over the other, not a bit of both.

Own best judge: Individuals are considered the best judge of their own type. While the MBTI questionnaire provides a Reported Type, this is considered only an indication of their probable overall Type. A Best Fit Process is usually used to allow the individual to develop their understanding of the four dichotomies, form their own hypothesis as to their overall Type and compare this against the Reported Type. In more than 20% of cases, the hypothesis and the reported type differ in one or more dichotomies: the clarity of each preference, any potential for bias in the report and, often, a comparison of two or more whole Types may then be used to help the subject determine his or her own Best Fit.

No right or wrong: No preference or total type is considered 'better' or 'worse' than another - they are all, as in the title of the book on this subject by Isabel Briggs Myers, Gifts Differing.

Voluntary: It is considered unethical to compel anyone to take the Myers-Briggs Type Indicator. It should always be taken voluntarily.

Confidentiality: The result of the MBTI Reported and Best Fit type are confidential between the individual and administrator and, ethically, not for disclosure without permission.

Not for selection: Because the MBTI measures preferences instead of aptitude - and because there are no right or wrong types - it is not considered a proper instrument for purposes of employment selection. Many professions contain highly competent individuals of different types with complementary preferences.

Importance of proper feedback: Individuals should always be given detailed feedback from a trained administrator and an opportunity to undertake a Best Fit exercise to check against their Reported Type. Feedback can be given in person or, where this is not practical, by telephone or electronically.

Applications of the MBTI

The indicator is frequently used in the areas of career counseling, pedagogy, group dynamics, employee training, marketing, leadership training, life coaching, executive coaching, marriage counseling, Workers' compensation claims and personal development.

Type dynamics and development

The Sixteen Types
ISTJ	ISFJ	INFJ	INTJ
ISTP	ISFP	INFP	INTP
ESTP	ESFP	ENFP	ENTP
ESTJ	ESFJ	ENFJ	ENTJ
The table organizing the sixteen types was created by Isabel Myers (an INFP).

U.S.A. Population Breakdown
ISTJ 11.6%	ISFJ 13.8%	INFJ 1.5%	INTJ 2.1%
ISTP 5.4%	ISFP 8.8%	INFP 4.3%	INTP 3.3%
ESTP 4.3%	ESFP 8.5%	ENFP 8.1%	ENTP 3.2%
ESTJ 8.7%	ESFJ 12.3%	ENFJ 2.4%	ENTJ 1.8%
Estimated percentages of the 16 types in the American population using inferential statistics. The figures above are from a random sampling of 3009 people culled from a total pool of 16,000 using the 1998 MBTI Form M. The individuals whose form results were used in this random sampling were not provided with the data to verify or question their accuracy. But these numbers do provide a working base on which to build further understanding and development of the model as extrapolated to larger populations. It should be noted that some types are more likely to take the MBTI than others (such as the INFP) and raw statistics prove unreliable because of this.

The interaction of two, three, or four preferences is known as type dynamics. For each of the sixteen four-preference types one function will be the most dominant and is likely to be evident earliest in life. A secondary or auxiliary function typically becomes more evident (differentiated) during teenage years and provides balance to the dominant. In normal development individuals tend to become more fluent with a third, tertiary function during mid life, whilst the fourth inferior function remains least consciously developed and is often considered to be more associated with the unconscious, being most evident in situations such as high stress (sometimes referred to as being in the grip of the inferior function).

The sequence of differentiation of dominant, auxiliary and tertiary functions through life is termed type development. This is an idealized sequence which may be disrupted by major life events, for example the death or serious illness of a parent during childhood is considered commonly to halt full development of the auxiliary function.

The dynamic sequence of functions and their attitudes can be determined in the following way:

• The overall lifestyle preference (J-P) determines whether the judging (T-F) or perceiving (S-N) preference is most evident in the outside world, i.e. which function has an extraverted attitude

• For those with an overall preference for Extraversion the function with the extraverted attitude will be the dominant function - for example, for someone with an ESTJ type the dominant function is their judging function, Thinking, and this is experienced with an extraverted attitude (this is notated as a dominant Te). The same would be true of an ENTJ whilst for an ESTP the dominant function will be the perceiving function, Sensing, notated as a dominant Se.

• The Auxiliary function for Extravert types is the less preferred of the Judging or Perceiving functions and it is experienced with an introverted attitude: for example, the auxiliary function for ESTJ is Introverted Sensing (Si) and the auxiliary for ENFP would be Introverted Feeling (Fi).

• For those with an overall preference for Introversion the function with the extraverted attitude is the auxiliary; the dominant is the other function in the main four letter preference. So the dominant function for ISTJ is Introverted Sensing (Si) with the auxiliary (supporting) function being Extraverted Thinking (Te).

• The Tertiary function is the opposite preference from the Auxiliary. For example, if the Auxiliary is Thinking then the Tertiary would be Feeling. The attitude of the Tertiary is the subject of some debate and therefore is not normally indicated, i.e. if the Auxiliary was Te then the Tertiary would be F (not Fe or Fi)

• The Inferior function is the opposite preference and attitude from the Dominant, so for an ESTJ with dominant Te the Inferior would be Fi.

Note that for those with an overall Extraversion preference the dominant function is the one most evident in the external world: whilst it is the auxiliary function that is most evident externally for Introverts, as their dominant function relates to the interior world.

A couple of examples of whole types will help to clarify this further.

Taking the ESTJ example above:

• Extraverted function is a Judging function (T-F) because of the overall J preference
• Extraverted function is dominant because of overall E preference
• Dominant function is therefore extraverted Thinking (Te)
• Auxiliary function will be the less dominant Perceiving function - introverted Sensing (Si)
• Tertiary function is the opposite preference to the Auxiliary - iNtuition (N)
• Inferior function is the opposite preference and attitude to the Dominant - introverted Feeling (Fi)

The dynamics of the ESTJ are found in the primary combination of Extraverted Thinking being their dominant function and Introverted Sensing being their auxiliary function: The dominant tendency to order the ESTJ's environment, to set clear boundaries, to clarify roles and timetables and to direct the activities around them is supported by the facility for using past experience in an ordered and systematic way to help organize themselves and other. ESTJs, for instance, may enjoy planning trips for groups of people to achieve some goal or to perform some culturally uplifting function. Because of their ease of directing others and their facility of managing their own time, they will engage all the resources at their disposal to achieve their goals. However, under prolonged stress or sudden trauma, ESTJs may overuse their Extraverted Thinking function and fall into "the grip" of their inferior function, Introverted Feeling. Though the ESTJ can seem insensitive to the feelings of others in their normal activities, under tremendous stress, they can suddenly express feelings of being unappreciated or wounded by insensitivity.

Looking at the diametrically opposite four-letter Type, INFP:

• Extraverted function is a Perceiving function (S-N) because of the P preference
• Introverted function is dominant because of the I preference
• Dominant function is therefore Introverted Feeling (Fi)
• Auxiliary function is Extraverted iNtuition (Ne)
• Tertiary function is the opposite of the Auxiliary, Sensing (S)
• Inferior function is the opposite of the Dominant, Extraverted Thinking (Te)

The dynamics of the INFP rest on the fundamental correspondence of Introverted Feeling and Extraverted iNtuition. The dominant tendency of the INFP is toward building a rich internal framework of values and toward championing human rights. They often devote themselves behind the scenes to causes such as civil rights or saving the environment. Since they tend to avoid the limelight, postpone decisions, and maintain a reserved posture, they are rarely found in executive-director type positions of the organizations that serve those causes. Normally, the INFP dislikes being "in charge" of things. When not under stress, the INFP radiates a pleasant and sympathetic demeanor; but under extreme stress, they can suddenly become rigid and directive, exerting their extraverted Thinking erratically.

Every type - and its opposite - is the expression of these interactions, which give each type its unique "signature" that can be recognized.

Correlations to other instruments

Keirsey Temperaments

David W. Keirsey mapped four 'Temperaments' to the existing Myers-Briggs system groupings SP, SJ, NF and NT; often resulting in confusion of the two theories. However, the Keirsey Temperament Sorter is not directly associated with the official Myers-Briggs Type Indicator.

ISITEJ	ISIFEJ	INIFEJ	INITEJ
Inspector	Protector	Counselor	Mastermind
ISETIP	ISEFIP	INEFIP	INETIP
Crafter	Composer	Healer	Architect
ESETIP	ESEFIP	ENEFIP	ENETIP
Promoter	Performer	Champion	Inventor
ESITEJ	ESIFEJ	ENIFEJ	ENITEJ
Supervisor	Provider	Teacher	Fieldmarshal

Big Five McCrae & Costa present correlations between the MBTI scales and the Big Five personality construct, which is a conglomeration of characteristics found in nearly all personality and psychological tests. The five personality characteristics are extraversion, openness, agreeableness, conscientiousness, and emotional stability (or neuroticism). The following study is based on the results from 267 men followed as part of a longitudinal study of aging. (Similar results were obtained with 201 women.)

	Extraversion	Openness	Agreeableness	Conscientiousness	Neuroticism
E-I	−0.74	0.03	−0.03	0.08	0.16
S-N	0.10	0.72	0.04	−0.15	−0.06
T-F	0.19	0.02	0.44	−0.15	0.06
J-P	0.15	0.30	−0.06	−0.49	0.11
The closer the number is to 1.0 or −1.0, the higher the degree of correlation.

These data suggest that four of the MBTI scales are related to the Big Five personality traits. These correlations show that E-I and S-N are strongly related to extraversion and openness respectively, while T-F and J-P are moderately related to agreeableness and conscientiousness respectively. The emotional stability dimension of the Big Five is largely absent from the original MBTI. (Though the TDI, discussed above, has addressed that dimension).

These findings led McCrae and Costa to conclude "There was no support for the view that the MBTI measures truly dichotomous preferences or qualitatively distinct types... Jung's theory is either incorrect or inadequately operationalized by the MBTI and cannot provide a sound basis for interpreting it."

Study of scoring consistency

Split-half reliability of the MBTI scales is good, although test-retest reliability is sensitive to the time between tests. However, because the MBTI dichotomies scores in the middle of the distribution, type allocations are less reliable. Within each scale, as measured on Form G, about 83% of categorizations remain the same when retested within nine months, and around 75% when retested after nine months. About 50% of people tested within nine months remain the same overall type and 36% remain the same after nine months. For Form M (the most current form of the MBTI instrument) these scores are higher (see MBTI Manual, p. 163, Table 8.6).

Criticism

Validity

Neither Katharine Cook Briggs nor Isabel Briggs Myers had any scientific qualifications in the field of psychometric testing. Furthermore, Carl Jung's theory of psychological type, which the MBTI attempts to operationalize, is not based on any scientific studies. Jung's methods primarily included introspection and anecdote, methods largely rejected by the modern field of psychology.

The statistical validity of the MBTI as a psychometric instrument has also been subject to criticism, in particular, the dichotomous scoring of dimensions. For example, some researchers expected that scores would show a bimodal distribution with peaks near the ends of the scales, but found that scores on the individual subscales were actually distributed in a centrally peaked manner similar to a normal distribution. A cut-off exists at the centre of the subscale such that a score on one side is classified as one type, and a score on the other side as the opposite type. This fails to support the concept of type--the norm is for people to lie near the middle of the subscale. Nevertheless, "the absence of bimodal score distributions does not necessarily prove that the 'type'-based approach is incorrect."

It has been estimated that between a third and a half of the published material on the MBTI has been produced for conferences of the Centre for the Application of Psychological Type (which provides training in the MBTI) or as papers in the Journal of Psychological Type (which is edited by Myers-Briggs advocates). It has been argued that this reflects a lack of critical scrutiny. Estimations on the research related to the most utilized tool published in fifty years (e.g. 40 million administrations) is affected by the popularity of the instrument.

Unlike other personality measures, such as the Minnesota Multiphasic Personality Inventory or the Personality Assessment Inventory, the MBTI lacks validity scales to assess response styles such as exaggeration or impression management.

Reliability

Some researchers have interpreted the reliability of the test as being low, with test takers who retake the test often being assigned a different type. According to surveys performed by the proponents of Myers-Briggs, the highest percentage of people who fell into the same category on the second test is only 47%. Furthermore, a wide range of 39% - 76% of those tested fall into different types upon retesting weeks or years later. When people are asked to compare their preferred type to that assigned by the MBTI, only half of people pick the same profile. Critics also argue that the MBTI lacks falsifiability, which can cause confirmation bias in the interpretation of results.

Utility

Although the proportion of different personality types varies between different careers the relevance of the MBTI for career planning has been questioned, with reservations about the relevance of type to job performance or satisfaction, and concerns about the potential misuse of the instrument in labelling individuals.

Skepticism

Skeptics criticize the terminology of the MBTI as being so vague as to allow any kind of behaviour to fit any personality type, resulting in the Forer effect, where an individual gives a high rating to a positive description that supposedly applies specifically to them. However, the descriptions offered for the 16 psychological types are often quite detailed and specific, unlike the "vague and general personality descriptions" that characterize the Forer effect. For example, David Keirsey examined how the four temperaments differ in terms of language use, intellectual orientation, educational and vocational interests, social orientation, self image, personal values, social roles and even characteristic hand gestures. Keirsey went on to describe the hierarchy of intellectual roles played by each of the four types within each temperament, resulting in sixteen unique descriptions which, unlike the Forer effect, rely not on the universal traits that make human beings the same, but on the specific traits that make human beings different from one another.