16Personalities vs MBTI: are they the same thing?

What is the MBTI, exactly?

The Myers-Briggs Type Indicator is the licensed instrument in the tradition built by Katharine Cook Briggs and Isabel Briggs Myers from Carl Jung's ideas about psychological types. It is owned today by The Myers-Briggs Company, and the official version is administered by a trained, certified practitioner, usually with a feedback conversation. It scores four either-or dichotomies, Extraversion or Introversion, Sensing or Intuition, Thinking or Feeling, and Judging or Perceiving, and combines the four letters into one of sixteen types, such as INFJ or ESTP.

Because it is delivered through certification, most people who say they have taken the MBTI have not sat the licensed instrument at all. They have taken a free imitation instead, and 16Personalities is by far the most widely taken of those.

What is 16Personalities?

16Personalities is a free online quiz that reports one of sixteen types written as a four-letter code, in the style made familiar by the MBTI, with a fifth letter, Assertive (A) or Turbulent (T), for what the site calls Identity. Its makers describe the model as their own, drawing on trait theory rather than the licensed MBTI instrument, at the time of writing. It is quick and well designed, which is why it is often the first personality test someone meets.

The fifth letter tracks roughly the ground the Big Five calls Emotional Stability, a dimension the official MBTI leaves out entirely. Adding it was a genuine improvement, though it is still a letter rather than a position on a scale, so the same trade-off applies to Identity as to the other four letters.

Why do the codes look the same if the tests are different?

Both instruments sort respondents along the same four historic dichotomies and print the result as a four-letter code, so an INFJ from one test looks identical on the page to an INFJ from the other. That resemblance is the point of borrowing the vocabulary, not evidence that the two questionnaires ask the same items or score them the same way: the official MBTI uses proprietary items controlled through certified practitioners, while 16Personalities publishes its own free test with a model the company describes as its own. Neither development process has been laid out for independent, peer-reviewed replication, so the fair comparison is between four-letter, type-based formats in general, not between the two brands' marketing claims.

What does the evidence say about four-letter types in general?

Three findings recur across the research on this format, and apply to any test that borrows it, official or not. First, the underlying scales behave as continuous traits rather than true either-or dichotomies: a large adult sample given the MBTI alongside a five-factor inventory showed no support for distinct types, with each of four scales lining up with a Big Five dimension instead (McCrae & Costa, 1989). Second, 160 adults who completed both the MBTI and the NEO-PI showed the same pattern, the four MBTI scales overlapping with four Big Five dimensions while Neuroticism related to none of them (Furnham, 1996). Third, a review for practitioners concluded the four-letter formula does not support the inferences commonly drawn from it, and urged considerable caution before acting on a type (Pittenger, 2005).

None of that means the four letters measure nothing. It means a type test rounds a continuous measurement to one side of a line. Each of these traits is a dimension people vary along by degree, and across a large sample the scores are roughly bell-shaped, with most people near the middle and few at either end (Goldberg, 1993). There is no natural cut-point in that distribution, which is why sorting people into two or four or sixteen boxes loses information, and why the same person can land in a different box on a retake when they sit near a line (McCrae & Costa, 1989). Two people one point apart on the same scale can be handed opposite letters without anything meaningful separating them.

Is a short online test like this reliable?

Reliability is separate from which brand wrote the test. Precision on a scale rises with the number of items that tap the same trait, and a quiz built to be quick and shareable is under constant pressure to trim items. Researchers who examined very short Big Five measures in two samples, of 437 employees and 355 students, found that abbreviated scales understated how much traits mattered for behaviour and inflated the apparent importance of other constructs, with single-item measures the worst offenders (Credé et al., 2012). Even a modestly longer scale improves validity substantially, at little cost in the respondent's time; what moves a free test off that curve is how many items sit behind each score, not whether it is free or paid.

16Personalities and the MBTI, side by side

Read either result as vocabulary, not measurement. A code is a shorthand for a position on several scales, and it always throws away how close to the middle that position was. See Wellington vs 16Personalities, Wellington vs MBTI, and Big Five vs MBTI for either test against the trait model researchers converged on.

How does Wellington measure this instead?

Wellington is a science-based personality assessment from Therabot Labs LLC. It measures personality as continuous traits, built on the Big Five and HEXACO models, and writes the results back as a personal report rather than a type.

Wellington measures each dimension rather than naming a box for you. The free Snapshot asks 60 questions and scores 6 continuous dimensions, the Big Five plus Honesty-Humility from the HEXACO model: Extraversion, Agreeableness, Conscientiousness, Emotional Stability, Openness to Experience and Honesty-Humility. The first ten questions are answered before anything is asked; after question ten you sign in with an email so your answers are saved and results can be shown. There is no card. The Wellington Membership adds the facets beneath each dimension and all 24 VIA character strengths, 90 traits in total, on a trait structure from decades of lexical research (Goldberg, 1993).

Every trait is reported as a percentile against the reference sample. The three bands (Quiet below the 30th percentile, Balanced to the 70th, High above) and the Portrait names exist to make the result easier to talk about; the percentile is the measurement, and it is always shown alongside. A Portrait name summarises the pattern of bands, a label chosen from the scores rather than a box that replaces them, and its low, medium and high letters are those same three bands under different names. Our reference norms are provisional while our norming sample is completed. Wellington is a wellness tool for reflection, not a medical or psychological diagnosis, and it does not replace care from a qualified professional.

Questions people ask

Is 16Personalities the same as the MBTI?

No. The official Myers-Briggs Type Indicator is a licensed instrument usually delivered through a certified practitioner. 16Personalities is a free online test that borrows the same four-letter naming style and adds a fifth Identity letter, but describes its model as its own, closer to trait theory, at the time of writing. Both report a type rather than a position on each scale.

Is 16Personalities accurate?

The four letters it borrows relate to real, measurable traits; studies of the MBTI-style format show its scales track four of the Big Five dimensions (Furnham, 1996; McCrae & Costa, 1989). What the evidence does not support is sorting people into sixteen discrete boxes: those same scales behave as continuous dimensions, and a review for practitioners concluded the four-letter formula does not carry the inferences commonly drawn from it (Pittenger, 2005). We are not aware of independent, peer-reviewed validation of the 16Personalities instrument itself; its site reports its own figures.

Why did my 16Personalities type change when I retook it?

Almost certainly because you sat near the middle on at least one of the five scales. Most people do, on most scales, and a type test forces a line-crossing choice where a trait score would simply show a small shift. Type-based scales measured this way behave as continuous dimensions rather than stable either-or categories (McCrae & Costa, 1989), so a slightly different mood or week is enough to flip a letter.