Assertive vs turbulent: what -A and -T mean after an MBTI type

You took a test and it said ISFP-T. Your friend took one and got ESFP-A. A third friend, who did hers at a work training day, got four letters and no hyphen, and now wants to know what the two of you did wrong.

Nobody did anything wrong. The letter after the hyphen stands for assertive or turbulent, and it comes from one particular website's test. It is not part of the Myers-Briggs instrument and never was. It measures something real, though, and something the four letters were deliberately built to leave out.

Where the fifth letter comes from

The suffix belongs to 16Personalities, a widely taken free test and the place many people first met their type online. Its questionnaire is called the NERIS Type Explorer, and it scores five scales rather than four. The first four carry the familiar letters. The fifth is called Identity, and its two ends are Assertive, written -A, and Turbulent, written -T.

The site is open about being a different thing from the MBTI. It describes the two as distinct, separately trademarked frameworks, and says its own model is a reworking of the Big Five personality traits that keeps the four-letter format because people already know it. It does not use the cognitive functions that Myers-Briggs theory is built on.

So a result like ISFP-T is a hybrid by design: four letters borrowed in form from one tradition, laid over five trait scales from another, with a fifth letter added for the scale that had no counterpart.

What assertive and turbulent measure

The Identity scale is about confidence and worry. As the site describes it, a person toward the assertive end is steady, not easily rattled, and not much given to second-guessing a decision once it is made. A person toward the turbulent end is more self-conscious, more of a perfectionist, quicker to notice what could go wrong, and keener to improve on the last attempt.

Neither word is used in its everyday sense, which causes two predictable misreadings. Assertive here does not mean pushy or outspoken. A quiet person who sleeps well the night before an exam is assertive in this sense. Turbulent does not mean chaotic or dramatic. A calm-looking person who rereads a sent email four times is turbulent.

Like the other scales on that test, Identity is reported as a percentage along a line. Somebody at 52 percent turbulent and somebody at 91 get the same letter, and they are not having the same week.

The other T

One practical confusion is worth clearing up, because it comes up constantly. A type code can now contain two different Ts.

The T in third position is thinking, the opposite of feeling. The T after the hyphen is turbulent, the opposite of assertive. They have nothing to do with each other. An INFJ-T is a feeling type who scored turbulent. An ESTJ-A is a thinking type who scored assertive. An INTP-T has one of each. Thinking vs feeling is not logic versus emotion covers the one in the middle.

Why the Myers-Briggs instrument has no such scale

The official instrument reports four preference pairs and stops. Its publisher, The Myers-Briggs Company, sells a more detailed version called Step II that divides each of the four pairs into five facets, twenty in all. Even there, nothing corresponds to assertive and turbulent.

The omission is old and has been remarked on. When Robert McCrae and Paul Costa compared the MBTI with the Big Five in the Journal of Personality in 1989, they matched each of its four scales to one of the five traits and found the fifth, neuroticism, without a partner. They called that the most conspicuous gap in the instrument and gave two reasons for it. Emotional steadiness was not part of how Jung defined his types. And the test's authors held that every type is equally valuable, a position that is hard to keep up about a trait where one end is plainly harder to live with.

That second reason is the heart of it. Isabel Briggs Myers built a questionnaire in which no result is bad news, and it is a large part of why people share their four letters so freely. A scale running from calm to anxious cannot be written that way, so it was never included.

The -A and -T suffix reads to me as that missing trait, brought back under gentler names. That is my interpretation and not a quotation: the site says its five scales are similar to the Big Five, and its account of the turbulent end, worry and self-doubt and sensitivity to stress, sits close to what trait researchers put under neuroticism. MBTI vs the Big Five sets the two systems side by side.

What changes between ISFP-A and ISFP-T

The four letters stay the same, so everything those letters describe stays the same. Both are people who recharge alone, attend to what is concretely in front of them, decide by what matters to the people involved and prefer to keep their options open. The ISFP page describes both of them.

What the suffix adds is how that person tends to feel about their own performance. Two ISFPs finish the same piece of work. One hands it in and goes to lunch. The other hands it in, thinks of an improvement on the stairs and is still turning it over at dinner. Same preferences, different weather.

The same holds across the table. An ESFP with an -A and one with a -T are equally sociable and equally spontaneous. One of them lies awake afterward wondering whether the joke landed.

It is tempting to read assertive as the good result. I would resist that. The steady end can shade into not noticing a problem until it is large, and the worried end is where a lot of careful work comes from. The label describes a cost and a benefit on each side.

How much to read into it

Less than the other four letters, in my view, and for a simple reason. A scale about worry is the one most obviously tied to how your month is going. Answer it during a job search and again a year into a job you like, and I would expect that reading to move before any of the others did. I have no study to cite for that and offer it only as common sense.

One thing it is not is a mental health measure. A turbulent result does not indicate an anxiety disorder and an assertive one does not rule anything out. No free personality questionnaire is a clinical or diagnostic instrument, that one and this one included. Worry that is getting in the way of ordinary life is a matter for someone qualified, not for a letter.

The test on this site reports four letters and no suffix. That is a choice about scope rather than a judgment on the fifth scale: the four are the ones the type descriptions are written around. How the sixty questions are scored shows what they add up to. If you arrived with an -A or a -T from somewhere else, drop it and the first four letters will find you the right one of the sixteen type pages.

MBTI is a trademark of The Myers-Briggs Company, and 16Personalities belongs to its own publisher. This site has no connection to either. I run it by myself and I am not a psychologist. If you would like a second reading of your four letters without the fifth, the test here takes about ten minutes.