Myers-Briggs Type Indicator

The Myers-Briggs Type Indicator (MBTI) assessment is a psychometric questionnaire designed to measure psychological preferences in how people perceive the world and make decisions. These preferences were extrapolated from the typological theories proposed by Carl Gustav Jung and first 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 to 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.

CPP Inc., the publisher of the MBTI instrument, calls it "the world’s most widely used personality assessment", with as many as two million assessments administered annually. Some academic psychologists have criticized the MBTI instrument, claiming that it "lacks convincing validity data". Proponents of the test, however, cite reports of individual behavior and have found that the indicator meets or exceeds the reliability of other psychological instruments. Some studies have found strong support for construct validity, internal consistency, and test-retest reliability, although variation was observed.

The definitive published source of reference for the Myers-Briggs Type Indicator is The Manual produced by CPP. However, the registered trademark rights to the terms Myers-Briggs Type Indicator and MBTI have been assigned from the publisher to the Myers-Briggs Type Indicator Trust.

Concepts
As the MBTI Manual states, the indicator "is designed to implement a theory; therefore the theory must be understood to understand the MBTI".

Fundamental to the Myers-Briggs Type Indicator is the theory of psychological type as originally developed by Carl Jung. Jung proposed the existence of two dichotomous pairs of cognitive functions: Jung went on to suggest that these functions are expressed in either an introverted or extraverted form. From Jung's original concepts, Briggs and Myers developed their own theory of psychological type, described below, on which the MBTI is based.
 * The "rational" (judging) functions: thinking and feeling
 * The "irrational" (perceiving) functions: sensing and intuition

Type
Jung's typological model regards psychological 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 are better or worse; however, Briggs and Myers theorized that individuals naturally prefer 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 types are typically referred to by an abbreviation of four letters—the initial letters of each of their four type preferences (except in the case of intuition, which uses the abbreviation N to distinguish it from Introversion). For instance:
 * ESTJ: extraversion (E), sensing (S), thinking (T), judgment (J)
 * INFP: introversion (I), intuition (N), feeling (F), perception (P)

And so on for all 16 possible type combinations.

Four dichotomies
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 who prefer judgment over perception 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 extroversion over introversion cannot be correctly described as more extroverted: 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). The expression of a person's psychological type is more than the sum of the four individual preferences. The preferences interact through type dynamics and type development.

Attitudes: Extroversion (E)/Introversion (I)
Myers-Briggs literature uses the terms extroversion and introversion  as Jung first used them, and preserves the original spelling of extroversion. Extroversion means "outward-turning" and introversion means "inward-turning." These specific definitions vary somewhat from the popular usage of the words.

The preferences for extroversion and introversion are often called as attitudes. Briggs and Myers recognized that each of the cognitive functions can operate in the external world of behavior, action, people, and things (extroverted attitude) or the internal world of ideas and reflection (introverted attitude). The MBTI assessment sorts for an overall preference for one or the other.

People who prefer extroversion draw energy from action: they tend to act, then reflect, then act further. If they are inactive, their motivation tends to decline. To rebuild their energy, extroverts need breaks from time spent in reflection. Conversely, those who prefer introversion expend energy through action: they prefer to reflect, then act, then reflect again. To rebuild their energy, introverts need quiet time alone, away from activity.

The extrovert's flow is directed outward toward people and objects, and the introvert's is directed inward toward concepts and ideas. Contrasting characteristics between extroverts and introverts include the following:
 * Extroverts are action oriented, while introverts are thought oriented.
 * Extroverts seek breadth of knowledge and influence, while introverts seek depth of knowledge and influence.
 * Extroverts often prefer more frequent interaction, while introverts prefer more substantial interaction.
 * Extroverts recharge and get their energy from spending time with people, while introverts recharge and get their energy from spending time alone.

Functions: Sensing (S)/Intuition (N) and Thinking (T)/Feeling (F)
Jung identified two pairs of psychological functions:
 * The two perceiving functions, sensing and intuition
 * The two judging functions, thinking and feeling

According to the Myers-Briggs typology model, each person uses one of these four functions more dominantly and proficiently than the other three; however, 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, which 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 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. 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.

As noted already, people who prefer thinking 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 who prefer feeling do not necessarily have "better" emotional reactions than their thinking counterparts.

Dominant Function
According to Myers and Briggs, people use all four cognitive functions. However, 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. Myers called this inferior function the shadow.

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: Judgment (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 held that types with a preference for judgment 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 like to "have matters settled." Those types who prefer perception 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, perceptive 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.

Historical development
Katharine Cook Briggs began her research into personality in 1917. Upon meeting her future son-in-law, she observed marked differences between his personality and that of other family members. Briggs embarked on a project of reading biographies, and she developed a typology based on patterns she found. She proposed four temperaments: Meditative (or Thoughtful), Spontaneous, Executive, and Social. Then, after the English translation of Psychological Types was published in 1923 (having first been published in German in 1921), she recognized that Jung's theory was similar to, yet went far beyond, her own. Briggs's four types were later identified as corresponding to the Is, EPs, ETJs and EFJs. Her first publications were 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).

Briggs's daughter, Isabel Briggs Myers, added to her mother's typological research, which she would progressively take over entirely. Myers graduated first in her class from Swarthmore College in 1919 and wrote the prize-winning mystery novel Murder Yet to Come in 1929 using typological ideas. However, neither Myers nor Briggs were formally educated in psychology, and thus they lacked scientific credentials in the field of psychometric testing. So Myers apprenticed herself to Edward N. Hay, who was then personnel manager for a large Philadelphia bank and went on to start one of the first successful personnel consulting firms in the U.S. From Hay, Myers learned test construction, scoring, validation, and statistics. 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.

Myers' work attracted the attention of Henry Chauncey, head of the Educational Testing Service, and under these auspices, the first MBTI Manual was published in 1962. The MBTI received further support from Donald T. McKinnon, head of the Institute of Personality Research at the University of California; Harold Grant, professor at Michigan State and Auburn Universities; and Mary H. McCaulley of the University of Florida. The publication of the MBTI was transferred to Consulting Psychologists Press in 1975, and the Center for Applications of Psychological Type (CAPT) was founded as a research laboratory. After Myers' death in May 1980, Mary McCaulley updated the MBTI Manual, and the second edition was published in 1985. The third edition appeared in 1998.

Judgment vs. perception
The most notable addition of Myers and Briggs to Jung's original thought is their concept that a given type's fourth letter (J or P) is determined by how that type interacts with the external world, rather than by the type's dominant function. The difference becomes evident when assessing the cognitive functions of introverts.

To Jung, a type with dominant introverted thinking, for example, would be considered rational (judging) because the decision-making function is dominant. To Myers, however, that same type would be irrational (perceiving) because the individual uses an information-gathering function (either extraverted intuition or extraverted sensing) when interacting with the outer world.

Orientation of the tertiary function
Jung theorized that the dominant function acts alone in its preferred world: exterior for the extraverts, and interior for the introverts. The remaining three functions, he suggested, operate together in the opposite world. If the dominant cognitive function is introverted, the other functions are extraverted, and vice versa. The MBTI Manual summarizes references in Jung's work to the balance in psychological type as follows: "There are several references in Jung's writing to the three remaining functions having an opposite attitudinal character. For example, in writing about introverts with thinking dominant...Jung commented that the counterbalancing functions have an extraverted character."

However, many MBTI practitioners hold that the tertiary function is oriented in the same direction as the dominant function. Using the INTP type as an example, the orientation would be as follows:
 * Dominant introverted thinking
 * Auxiliary extraverted intuition
 * Tertiary introverted sensing
 * Inferior extraverted feeling

From a theoretical perspective, noted psychologist H.J. Eysenck calls the MBTI a moderately successful quantification of Jung's original principles as outlined in Psychological Types. However, both models remain theory, with no controlled scientific studies supporting either Jung's original concept of type or the Myers-Briggs variation.

Applications
The indicator is frequently used in the areas of pedagogy, career counseling, team building, group dynamics, professional development, marketing, family business, leadership training, executive coaching, life coaching, personal development, marriage counseling, and workers' compensation claims.

Format and administration
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. At the time of her death, she was developing a more in-depth method of measuring how people express and experience their individual type pattern. This tool is called the MBTI Step II.

The Step III instrument is now available. It was developed in a joint project involving the following organizations: CPP, the publisher of the whole family of MBTI works; CAPT (Center 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 addresses type development and the use of perception and judgment by respondents.

In addition, the Type Differentiation Indicator (TDI) (Saunders, 1989) is a scoring system for the longer MBTI, Form J, which includes the 20 subscales above, plus a Comfort-Discomfort factor (which purportedly corresponds to the missing factor of Neuroticism). This factor includes seven additional scales to indicate a sense of overall comfort and confidence versus discomfort and anxiety: guarded-optimistic, defiant-compliant, carefree-worried, decisive-ambivalent, intrepid-inhibited, leader-follower, and proactive-distractable. Also included is a composite of these called "strain." Each of these comfort-discomfort subscales also loads onto one of the four type dimensions, for example, proactive-distractable 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 0.50, "an acceptable result given the brevity of the subscales" (Saunders, 1989).

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 people 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 respondents to develop their understanding of the four dichotomies, to form their own hypothesis as to their overall Type, and to compare this against the Reported Type. In more than 20% of cases, the hypothesis and the Reported Type differ in one or more dichotomies. Using the clarity of each preference, any potential for bias in the report, and often, a comparison of two or more whole Types may then help respondents determine their own Best Fit.


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


 * 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: The results of the assessment should not be used to "label, evaluate, or limit the respondent in any way" (emphasis original). Since all types are valuable, and the MBTI measures preferences rather than aptitude, the MBTI 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. This feedback can be given in person or, where this is not practical, by telephone or electronically.

Type dynamics and development
The interaction of two, three, or four preferences is known as type dynamics. Although type dynamics has garnered little or no empirical support to substantiate its viability as a scientific theory, Myers and Briggs asserted that for each of the 16 four-preference types, one function is 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, while the fourth, inferior function remains least consciously developed. The inferior function 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. Note that this is an idealized sequence that may be disrupted by major life events.

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
 * The attitude preference (E-I) determines whether the extraverted function is dominant or auxiliary
 * For those with an overall preference for extraversion, the function with the extraverted attitude will be the dominant function. For example, for an ESTJ type the dominant function is the judging function, thinking, and this is experienced with an extraverted attitude. This is notated as a dominant Te. For an ESTP, the dominant function is the perceiving function, sensing, notated as a dominant Se.
 * The Auxiliary function for extraverts is the secondary preference 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 ESTP is introverted thinking (Ti).
 * 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 extraverts, the dominant function is the one most evident in the external world. For introverts, however, it is the auxiliary function that is most evident externally, as their dominant function relates to the interior world.

Some examples of whole types may 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 is the preferred perceiving function: introverted sensing (Si)
 * Tertiary function is the opposite of the Auxiliary: intuition
 * Inferior function is the opposite of the Dominant: introverted feeling (Fi)

The dynamics of the ESTJ are found in the primary combination of extraverted thinking as their dominant function and introverted sensing as their auxiliary function: the dominant tendency of ESTJs to order their environment, to set clear boundaries, to clarify roles and timetables, and to direct the activities around them is supported by their facility for using past experience in an ordered and systematic way to help organize themselves and others. For instance, ESTJs may enjoy planning trips for groups of people to achieve some goal or to perform some culturally uplifting function. Because of their ease in directing others and their facility in managing their own time, they 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. Although 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
 * 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, recognizable signature.

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

Big Five
McCrae and 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.)

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, the formulators of the Five Factor Theory, to conclude, "correlational analyses showed that the four MBTI indices did measure aspects of four of the five major dimensions of normal personality. The five-factor model provides an alternative basis for interpreting MBTI findings within a broader, more commonly shared conceptual framework." However, "there was no support for the view that the MBTI measures truly dichotomous preferences or qualitatively distinct types, instead, the instrument measures four relatively independent dimensions."

Origins of the theory
Jung's theory of psychological type, as published in his 1921 book, was not tested through controlled scientific studies. Jung's methods primarily included clinical observation, introspection and anecdote&mdash;methods that are largely regarded as inconclusive by the modern field of psychology.

Jung's type theory introduced a sequence of four cognitive functions (thinking, feeling, sensing, and intuition), each having one of two orientations (extraverted or introverted), for a total of eight functions. The Myers-Briggs theory is based on these eight functions, although with some differences in expression (see Differences from Jung above). However, neither the Myers-Briggs nor the Jungian models offer any scientific, experimental proof to support the existence, the sequence, the orientation, or the manifestation of these functions.

Validity
The statistical validity of the MBTI as a psychometric instrument has been the subject of criticism. 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 Center 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.

In 1991, the National Academy of Sciences committee reviewed data from MBTI research studies and concluded that only the I-E scale has adequate construct validity in terms of showing high correlations with comparable scales of other instruments and low correlations with instruments designed to assess different concepts. In contrast, the S-N and T-F scales show relatively weak validity. The 1991 review committee concluded at the time there was "not sufficient, well-designed research to justify the use of the MBTI in career counseling programs". However, this study also based its measurement of validity on "criterion-related validity (i.e., does the MBTI predict specific outcomes related to interpersonal relations or career success/job performance?)." The ethical guidelines of the MBTI assessment stress that the MBTI type "does not imply excellence, competence, or natural ability, only what is preferred." The 2009 MBTI Form M Manual Supplement states, "An instrument is said to be valid when it measures what it has been designed to measure (Ghiselli, Campbell, & Zedeck, 1981; Murphy & Davidshofer, 2005)." Studies have found that the MBTI scores compare favorably to other assessments with respect to evidence of convergent validity, divergent validity, construct validity, internal consistency, and test-retest reliability.

The accuracy of the MBTI depends on honest self-reporting by the person tested. Unlike some personality measures, such as the Minnesota Multiphasic Personality Inventory or the Personality Assessment Inventory, the MBTI does not use validity scales to assess exaggerated or socially desirable responses. As a result, individuals motivated to do so can fake their responses, and one study found that the MBTI judgment/perception dimension correlates with the Eysenck Personality Questionnaire lie scale. If respondents "fear they have something to lose, they may answer as they assume they should." However, the MBTI ethical guidelines state, "It is unethical and in many cases illegal to require job applicants to take the Indicator if the results will be used to screen out applicants." The intent of the MBTI is to provide "a framework for understanding individual differences, and … a dynamic model of individual development".

With regard to factor analysis, one study of 1291 college-aged students found six different factors instead of the four used in the MBTI. In other studies, researchers found that the JP and the SN scales correlate with one another.

Reliability
Some researchers have interpreted the reliability of the test as being low. Studies have found that between 39% and 76% of those tested fall into different types upon retesting some weeks or years later.

One study reports that the MBTI dichotomies exhibit good split-half reliability; however, the dichotomy scores are distributed in a bell curve, and the overall type allocations are less reliable. Also, test-retest reliability is sensitive to the time between tests. Within each dichotomy scale, as measured on Form G, about 83% of categorizations remain the same when individuals are retested within nine months, and around 75% when individuals are retested after nine months. About 50% of people tested within nine months remain the same overall type, and 36% remain the same type after more than nine months. For Form M (the most current form of the MBTI instrument), the MBTI Manual reports that these scores are higher (p. 163, Table 8.6).

In one study, when people were asked to compare their preferred type to that assigned by the MBTI assessment, only half of people picked the same profile. Critics also argue that the MBTI lacks falsifiability, which can cause confirmation bias in the interpretation of results.

Statistical structure
The instrument's dichotomous scoring of dimensions has also been subject to criticism. 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 center 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."

Utility
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 labeling individuals. In her original research, Isabel Myers found that the proportion of different personality types varied by choice of career or course of study. However, some other researchers examining the proportions of each type within varying professions report that the proportion of MBTI types within each occupation is close to that within a random sample of the population.

Studies suggest that the MBTI is not a useful predictor of job performance. In 1991 three scholars at the University of Western Ontario analyzed the results of 97 independent studies that evaluated the effectiveness of personality tests in predicting job success and job satisfaction ("Personnel Psychology," winter 1991). The results of the nationwide study found that the MBTI was not an effective tool in predicting individual performance or satisfaction in a corporate setting: "The validity coefficient for personality tests in predicting job success was found to average 0.29 (on a scale of 0 to 1). The corresponding average validity for the MBTI, however, was a weak 0.12. In fact, each study that examined the MBTI found its validity to be below acceptable levels of statistical significance." As noted above under Precepts and ethics, the MBTI measures preference, not ability. The use of the MBTI as a predictor of job success is expressly discouraged in the Manual. It is not designed for this purpose.

Skepticism
Skeptics criticize the terminology of the MBTI as being so "vague and general" as to allow any kind of behavior to fit any personality type. They claim that this results in the Forer effect, where individuals give a high rating to a positive description that supposedly applies specifically to them. Others argue that while the MBTI type descriptions are brief, they are also distinctive and precise. Some theorists, such as David Keirsey, have expanded on the MBTI descriptions, providing even greater detail. For instance, Keirsey's descriptions of his four temperaments, which he correlated with the sixteen MBTI personality types, show how the temperaments differ in terms of language use, intellectual orientation, educational and vocational interests, social orientation, self image, personal values, social roles, and characteristic hand gestures.

References and further reading

 * Hunsley, J.; Lee, C.M.; and Wood, J.M. (2004). Controversial and questionable assessment techniques. Science and Pseudoscience in Clinical Psychology, Lilienfeld SO, Lohr JM, Lynn SJ (eds.). Guilford, ISBN 1-59385-070-0
 * Bess, T.L.; and Harvey, R.J. (2001, April). Bimodal score distributions and the MBTI: Fact or artifact? Paper presented at the Annual Conference of the Society for Industrial and Organizational Psychology, San Diego.
 * Bess, T.L.; Harvey, R.J.; and Swartz, D. (2003). Hierarchical Confirmatory Factor Analysis of the Myers-Briggs Type Indicator Paper presented at the Annual Conference of the Society for Industrial and Organizational Psychology, Orlando.
 * Bourne, Dana (2005). Personality Types and the Transgender Community. Retrieved November 14, 2005
 * Falt, Jack. Bibliography of MBTI/Temperament Books by Author. Retrieved December 20, 2004
 * Georgia State University. GSU Master Teacher Program: On Learning Styles. Retrieved December 20, 2004.
 * Jung, Carl Gustav (1965). Memories, Dreams, Reflections. Vintage Books: New York, 1965. p. 207
 * Jung, C. G. (1971). Psychological types (Collected works of C. G. Jung, volume 6). (3rd ed.). Princeton, NJ: Princeton University Press. First appeared in German in 1921. ISBN 0-691-09770-4
 * Killian, Shaun (2007). More About the MBTI, personality and its impact on your effectiveness, MBTI Online.
 * Matthews, Paul (2004). The MBTI is a flawed measure of personality. bmj.com Rapid Responses. Retrieved February 9, 2005
 * Myers, Isabel Briggs (1980). Gifts Differing: Understanding Personality Type. Davies-Black Publishing; Reprint edition (May 1, 1995). ISBN 0-89106-074-X
 * Pearman, R.; Lombardo, M.; and Eichinger, R.(2005). YOU: Being More Effective In Your MBTI Type. Minn.:Lominger International, Inc.
 * Pearman, R.; and Albritton, S. (1996). I'm Not Crazy, I'm Just Not You: The Real Meaning of the Sixteen Personality Types. Mountain View, Ca: Davies-Black Publishing.
 * Personality Plus. Employers love personality tests. But what do they really reveal?
 * Saunders, D. (1989). Type Differentiation Indicator Manual: A scoring system for Form J of the Myers-Briggs Type Indicator. Palo Alto, CA: Consulting Psychologists Press, Inc.
 * Skeptics Dictionary. "Myers-Briggs Type Indicator"
 * Virginia Tech. The Relationship Between Psychological Type and Professional Orientation Among Technology Education Teachers. Retrieved December 20, 2004

Official websites

 * Association for Psychological Type International
 * Center for Applications of Psychological Type (CAPT)
 * CPP, Publisher of the MBTI
 * The Myers & Briggs Foundation
 * Murphy-Meisgeier Type Indicator for Children (MMTIC) at CAPT website
 * Psychometrics Canada, Canadian publisher of French and English MBTI

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