MBTI Relevancy

The MBTI was developed by Katherine Briggs and her daughter Isabel and describes 4 scales that combine to describe each person with one of 16 possible types (see Section 2.2.1.1). The MBTI is a general model of personality (Isachsen & Berens 1998), though has found prominent use in corporate environments (Burnett 2013; Dattner 2008; Stromberg 2014). Despite appearing in only one of the 147 studies examined (see Section 2.2.1), the MBTI was included in this review because of its presence and spending power in the corporate world (Dattner 2008; Burnett 2013; Stromberg 2014) which qualifies it as a model worth considering for widespread use and recognition.

3.1.1.1 Area of Use of the MBTI

As can be seen in Section 2.2.1, the MBTI does not feature heavily in academic literature, although it is the basis of some research in different fields like being used in accordance with pedagogy and different learning styles (Muller & Pennington 2014). The MBTI is primarily used in corporate settings for purposes such as recruitment and team building, offering guidelines and advice on how to approach interactions with individuals of specific personality types whether it be within a team or between subordinates and superiors. An estimate of two million Americans a year take the MBTI with 89 companies out of the US Fortune 100 making use of it (Dattner 2008; Stromberg 2014).

The MBTI's success in a corporate setting is supported by a number of professional organizations providing a variety of services. The Center for Applications of Psychological Type offers services such as training for administration and interpretation of the test, help with scoring, and maintains a database of MBTI profiles (Pittenger 2005). The Association of Psychological Type (APT) represents the interests of professionals who use the MBTI and also provide workshops that train non-psychologists to purchase and administer the MBTI in nonclinical settings (Pittenger 2005).

Methodology Personality Model Selection

40 3.1.1.2 Validity and Rejection of the MBTI

Despite its widespread use in corporate settings, the MBTI is greatly criticized and regarded as a flawed model of personality as indicated by the review of the area (see Section 2.2.1). Several of these validity problems are highlighted in the following sections.

3.1.1.2.1 Flawed Theoretical Foundation

The first prominent means of assessing the validity of a model is its theoretical basis or the claims that it makes and the theory that underlies it. In this context, validity is referring to the degree to which a test measures what it sets out to measure (Pittenger 2005).

3.1.1.2.1.1 Factor Analysis

Factor analysis is a type of statistical procedure that consists of making an analysis of the correlations among the questions in the test (Pittenger 2005). This analysis is undertaken on questionnaires typical to each model of personality and should reveal that there are distinct and separate clusters or factors in the questions being posed which should align with the theoretical factors of the theory of personality in question.

Working with the theory that the MBTI model proposes four dimensions that are unique and stand alone, analysis of the questions should reveal that each question correlates to a single factor and that in total there will be four factors. However, studies have found that this is not the case. For example, a study using 1,291 college aged students found six different factors and a high level of measurement error that lead the authors to conclude that their results were inconsistent with the MBTI theory (Sipps et al. 1985). Other research has also called the Judging-Perceiving and Sensing-Intuition scales into question as they found correlations between one another, thus weakening the MBTI's claim that there are four distinct factors at play (McCrae & Costa 1989).

3.1.1.2.1.2 Predictive Power

Another measure of the theoretical soundness of a model is the predictive power of its measures when compared to its base theory. That is to say that the results of a personality profile should be usable as data to predict certain outcomes relating to the individual or even the population the test is administered on.

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For example, the purpose of the MBTI model's existence at all is to predict certain aspects of one's life based on their personality. It has frequently been used in the context of an individual's work and career, claiming to have an amount of insight into the kinds of people who end up in certain professions (Isachsen & Berens 1998). Advocates of the model may paint in broad strokes and claim that certain types dominate certain professions and that the type of an individual is thus telling of what career choices are more comfortable for that person. The problem here is that those claims tend to lack other contextual information that may explain this correlation. For example, nurses tend to have a different distribution of type as compared to managers. While the MBTI type could be the distinguishing factor between the two populations, there are alternative interpretations to that data. For example the fact that nursing has been and remains a profession dominated by women is a much more likely reason for disparity between the groups (Pittenger 2005). That is not to say that the types could not be a factor for profession distribution, but data suggests the proportion of MBTI types within each occupation is equivalent to that of a random sample of the population (Pittenger 2005).

3.1.1.2.2 Tool Reliability

Reliability refers to the consistency of a test between measurements, resulting in similar (or ideally the same) results every time the test is administered (Pittenger 2005). The MBTI claims that a person's type is immutable and doesn't change in their life time (Isachsen & Berens 1998). It would thus be expected that the reliability of the MBTI is extremely high and subsequent retests always yield the same or at least similar results.

The primary method for testing this reliability is to administer the same test to an individual on two occasions with the interval between the test and retest can range between several weeks to more than a year (Pittenger 2005). With the understanding that a person's personality does not change over time, this interval should have little to no change in someone's resulting profile. However, studies have shown that although the proportion of reclassification into the same category can be as high as 90%, the range drops to as low as 50% over a 5-week interval for the MBTI (Boyle 1995; Pittenger 2005).

Methodology Personality Model Selection

42 3.1.1.3 Final Analysis of the MBTI

In summary, the MBTI fails on a number of points in relation to validity: first, whether or not the dimensions described by the theory really exist (investigated via factor analysis); second, whether knowing a person's profile really gives someone predictive power over the target individual's behaviour in different circumstances; and third, whether the results of the testing are consistent over time (Pittenger 2005). In those ways, the MBTI falls short of the mark, is often ignored in academic research fields and will not be used for the purposes of this project.