The Open Psychometrics MBTI Test, Checked Against Its Own Data

Nearly everyone typing this is looking for the Open Extended Jungian Type Scales, known as the OEJTS. It lives on the OEJTS page at openpsychometrics.org, a research hobby site that hosts dozens of free personality measures and shares the anonymous answers it collects. Your result is four letters of the kind the MBTI made famous, plus a number showing where you landed on every scale behind it. The site states on the test page that the result is for educational or entertainment use only.

Same four letters, new questions

The Myers-Briggs Type Indicator, or MBTI, is a trademarked questionnaire. Its publisher sells it, often packaged with a session where a certified practitioner explains the result. The OEJTS uses the same four pairs of letters (whether you lean inward or outward, toward facts or patterns, logic or values, plans or options), but its questions and its scoring were written from scratch. The site calls it an open source alternative to the Myers-Briggs. So the OEJTS targets the same four letters with no tie to the company that owns the name, and it is not the trademarked questionnaire. A type from one can differ from a type from the other.

The $50 test and the free copies

You cannot take the trademarked questionnaire for free. The official online version usually runs around $50, more with a practitioner session, and our page on what the paid MBTI costs and includes covers the options. What costs nothing are copies of the idea that share its four scales. Among those, the OEJTS hides the least: no email, no account, and no upsell at the end. The trade is that your answers are saved anonymously and may be used for research.

The .org research site vs the .net lookalike

Check the address bar before you start. Search results for this test often include openpsychometrics.net, a separate site with a near-identical name. Its MBTI-style page runs a far longer quiz called the Cognitive Archetypes Test, claims retest reliability above 0.85, and lists two references with no volume, page numbers, or DOI (the permanent ID a published paper carries). Nobody can trace those sources. The .org site is the one that built the OEJTS and shares its data. If the site wants hundreds of answers, you are on the wrong site. The simplest habit is to bookmark the .org test page and start from there each time, rather than clicking whichever result appears first in a search.

The OEJTS test was built from the answers of people who already knew their type. The site wrote a pool of 278 candidate items and gave them to 25,568 volunteers who said they had spent at least two hours learning about Myers-Briggs types and felt confident about their own. It kept the items that best split the two sides of every scale. That cut left 48 items, twelve per scale. The full development notes for the Open Extended Jungian Type Scales are public.

That method has one clear strength and one clear limit. The items are good at predicting the type people already believed they had. They were never checked against how people behave at work, which the accuracy section below comes back to.

Three item counts, one test

People argue online about how long the OEJTS is, and they are all partly right, because three numbers circulate:

• 32 items: a PDF of the OEJTS 1.2 that circulates online lists 32 items and quotes about five minutes.
• 48 items: the development write-up describes 48 items, split evenly so every scale gets twelve.
• 60 items: the live test page, itself labeled OEJTS 1.2, has 60 items in two sections and quotes five to seven minutes. Per the development page, 40 of those are scored and 20 are experimental items being tried out.

If you took it recently on openpsychometrics.org, you took the 60-item version. If a friend quotes 32, they probably used the circulating PDF, which carries the same 1.2 label as the site. Whichever version you sat, the letters come out of the same four scales.

How your four letters get scored

The live version has two kinds of items. In the first section, each item puts two opposite descriptions at the ends of a five-point line, such as honest at one end and a liar at the other, and you mark where you fall. In the second section, you rate first-person statements by how true they are of you. Each answer adds to or takes away from one of the four scale totals.

The scoring is fixed arithmetic, the same for everyone, with no hidden weighting. Whichever side of the midpoint a total lands on becomes your letter for that scale. Because the method is published, a patient person could score a result by hand, and few free type tests allow that. Identical answers always produce an identical type, so any difference between your two attempts comes from you, not the software.

OEJTS results come as four letters plus a number for every scale. The score deserves more of your attention. A letter tells you which side of the midpoint you landed on. The score tells you how far.

Picture each scale as a line with a midpoint. Someone far out toward Introversion and someone one point past the middle both get an I. The letters match; the people do not. Go scale by scale and sort your letters into two groups: the ones well clear of the middle, and the ones sitting close to it. The first group is what you can rely on. Save a screenshot of the scale scores, not only the letters, so you can line them up against any retake.

Borderline letters and why retests change

Letters near the midpoint are the ones that flip. Your answers shift a little with mood, a recent week at work, and how you happen to read a question, and near the middle a small shift is enough to cross the line. That is why many people who retake a four-letter test see one letter change, and why it is nearly always their closest scale. The official MBTI has the same problem: studies of it find that plenty of people land on another type when retested after a gap of weeks.

If a letter sits near the middle, write down the two candidate types, for example INTJ and INTP, and read both descriptions against a normal week. Then retake it a month later and compare the scale scores, not the letters. A scale that swings is telling you the preference is weak or depends on the setting, which is worth knowing in itself. If you think a letter came out wrong, our guide on spotting a mistyped result walks through the usual causes.

Here is how that looks in practice. Say your result reads INFJ, with Introversion far from the center, Intuition and Feeling clearly on their side, and Judging only just past the midpoint. The I, N and F are the stable core. The J could go either way on a given day, so read the INFP description too. Whichever one matches how you handle deadlines and open plans is the better guide.

How well the OEJTS matches a known type

Openpsychometrics.org published a statistical comparison of the OEJTS with other online tests. After people finished the OEJTS, the site asked whether they already knew their type, and if so, what it was. It then measured how cleanly each test's scales separated the people who reported each letter. The comparison groups were 1,076 people for HumanMetrics, 996 for SimilarMinds, and 449 for 16Personalities.

On the I/E, T/F and J/P scales, the OEJTS scales separated the two groups 25 to 40 percent better than the next best test. On Sensing versus Intuition it came out about even with its best rival. If you went in already knowing your type, the OEJTS is more likely than those three to hand the same type back, on three letters out of four.

Two caveats come with that. The same site that built the test ran the study. And a person's known type was whatever they said it was, often from another free test, so the yardstick is itself a self-report.

Reliability, validity, and what the OEJTS has shown

Psychometrics is the branch of psychology that builds and checks tests of mental traits. By that yardstick, any MBTI-style questionnaire is a psychometric test: it has items, a scoring rule, and scales. The better question is how well it does the job, and two words settle that. Reliability means a test gives consistent results. Validity means it measures what it says it measures and predicts something useful. The OEJTS has fair evidence that it is consistent and that it matches the type people report. It has no evidence that it predicts how you will do in a job, and the site never says otherwise.

Jung, the Briggs-Myers pair, and the midpoint problem

The four letters trace back to Psychological Types, a 1921 book by the Swiss psychiatrist Carl Jung. In the 1940s a mother and daughter, Katharine Cook Briggs and Isabel Briggs Myers, turned his ideas into a questionnaire. Some of the traits underneath hold up well. Introversion and extraversion, for one, appear in nearly every modern model of personality. The weak point is the sorting. On most scales, the bulk of people land close to the center rather than in two neat camps, so cutting each scale into two letters throws information away and makes borderline people flip. That is the main scientific complaint about type tests, and it applies to free and official versions alike. The OEJTS softens it by showing your scale scores, so read those before the letters.

Which free tests show their numbers

Among the free MBTI tests, only one has put public numbers behind its accuracy. On evidence anyone can inspect, the OEJTS comes first: it shows how its items were chosen, shares its raw data, and reports a comparison against three rivals. HumanMetrics and 16Personalities have far bigger audiences but publish much less about how well their scales perform. The older of the two gets its own write-up on our HumanMetrics MBTI test page. Truity sits in the middle, with a carefully made test and no open data. The official MBTI has the largest body of research, much of it from its publisher, and alone among these charges up front.

OEJTS vs 16Personalities side by side

These are the two tests most people end up choosing between. The OEJTS is short, plain, and checkable: five to seven minutes, a bare results page, and scores you could recompute. 16Personalities runs a few questions more and returns a long, well-written profile showing a percentage for every scale. Its type names, such as the Architect and the Mediator, are what most people quote. Its results carry a fifth letter too, for how steady or restless you tend to feel, so its types do not line up exactly with the classic sixteen. Pick the OEJTS if you care how the number was made. Pick 16Personalities if you want something readable to share. Taking both costs nothing and helps you catch a borderline letter, and our 16Personalities career test page goes further on that one.

Good fits for the OEJTS

The OEJTS suits three kinds of people well. The curious, who want a fast, free look at their preferences without an account. The data-minded, who like checking how a result was made. And anyone checking a type they got somewhere else, since a second opinion from fresh questions helps on a close letter. It is also a good pick for a team exercise where nobody wants to pay or sign up.

Using an MBTI-style result for a career decision

Career choice is where the OEJTS runs out. The four letters describe preferences: whether you prefer company or solitude, detail or the big picture. A preference is the way you would rather work. It does not show your strengths, or what a job's pace and people will cost you over a year. The site itself says the result is for educational or entertainment use, and research on type has not shown that any four-letter code predicts success in a given job. For more on where type helps in a job hunt, read our page on using Myers-Briggs types in a career search.

Whether you are choosing a major or ten years into a job and thinking about leaving, use your type as a source of questions. With a shortlist of roles in hand, search each one on O*NET OnLine for its daily tasks and required skills.

Your four letters say which way you lean. Choosing a career takes two more answers: where your strengths lie, and which kinds of work you could stick with for years without wanting out. Type tests were designed for neither.

Pigment starts from a different place. Each question sets a few statements side by side and asks you to pick the one most like you. Your results come as a 36-page read: strengths, each paired with a way to put it to use; the way your thinking runs; the working styles and kinds of work you gravitate to; how to work with people whose style differs from yours; and, last, career recommendations: specific roles, and why your profile points there. It also covers what sustains you, beyond what you can do.

Pigment is young, and no peer-reviewed study has examined the test itself yet. Its design draws on published studies of how people fit their jobs and of putting strengths to use, so weigh it next to your own work history, not instead of it. If your OEJTS result left you wondering where it leads, this is a step that ends in roles you can look into.

Turn a Four-Letter Lean Into a Shortlist of Roles

Your OEJTS type shows how you lean. Pigment names your strengths and suggests roles to explore, all in 36 pages, for $79.99.

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