Using personality tests decently: what to do and what not to
Published 24/07/2026 · 2 min read
These tests are genuinely useful for understanding yourself and genuinely bad for sorting other people. Where is the line?
This is written from a learning-and-development background, so let us start with the part most often abused.
Do not use them to hire or to screen out
Tests of this family have modest test-retest reliability — take one again a few months later and a noticeable share of people get a different result. Using that to decide who gets a job is unfair to the candidate and a risk to the organisation.
Do use them to open a conversation
- In a team: talk about how each person wants work assigned and feedback given.
- On yourself: treat the weaknesses as a checklist, not as an excuse.
- When coaching: ask "which part of this fits you best?" rather than announcing someone's result to them.
The world's best-known personality test was written by two people with no psychology training
Katharine Cook Briggs began reading Carl Jung in the 1920s and was gripped by his idea of types. Her daughter, Isabel Briggs Myers, was a writer — she had won a prize for a detective novel. Neither had any training in psychology.
During the Second World War, Isabel set about building a questionnaire with a specific and rather decent aim: to help women entering factory work find a post that suited them, so they would be less miserable and better at it. She taught herself questionnaire construction and scoring largely as she went. The indicator was not published commercially until 1975.
Two things need saying, and both matter. That its authors held no degree does not make the tool worthless — plenty of useful things were built outside universities. But it does explain why the model stayed with binary types long after psychology had moved to continuous scales, and why its stability on retest remains the heaviest criticism against it.
The most striking detail is the original motive: helping people find somewhere they would fit. That is still the best use of any personality test. The worst use — keeping someone out of an opportunity — runs against the reason it was made.
One sign a test is honest
A good test tells you when your result sits near the middle. If your answers were nearly even on a dichotomy, the four-letter label does not describe you, and an honest instrument says so instead of handing you a flattering name.
MBTI® is a registered trademark of The Myers & Briggs Foundation. The test on Thấu Mình is not the official instrument; it is built on Carl Jung's four dichotomies with questions written here.