Key points
- The short answer: Big Five questionnaires have the most research behind them, and one of them, the IPIP-NEO-120, is free and measures 30 facets with 120 public-domain items (Johnson, 2014).
- In a review of prospective studies on 3 life outcomes (mortality, divorce and job attainment), personality traits predicted about as well as socioeconomic status and cognitive ability (Roberts et al., 2007).
- When 1,431 English trait adjectives were analyzed, the same five broad factors came out in 10 different analyses (Goldberg, 1990).
- Samples of 7,134 people answering six translations of the NEO-PI-R, including Portuguese, Chinese and Japanese, showed a structure similar to the American one (McCrae and Costa, 1997).
Ana's two results
Ana is 34 and teaches a class of nine-year-olds. In January she took a popular type test and got one four-letter result. In May, on a slow Sunday, she took it again and got a different one. Two of the four letters had flipped.
She wasn't upset, just puzzled. Had she changed? Was the test wrong? Or was she somewhere near the middle, where a small change in mood tips the label? Her real question was simple: which personality test should I actually trust?
Ana isn't a real person, but her two results are a common experience. Here is what accuracy means for a personality test, how the common tests compare in plain facts, and what Ana found out.
What the research says
trait adjectives analyzed. The same five factors appeared across 10 different analyses.
Goldberg, 1990people in six translated samples showed a five-factor structure close to the American one.
McCrae and Costa, 1997Effects on mortality, divorce and job attainment were about as large as those of income level and cognitive ability.
Roberts et al., 2007None of this makes one test "the best". It means the Big Five has the deepest record of being checked, across languages and over time, which is what "accurate" can fairly mean.
What "accurate" means for a personality test
Psychologists check two things.
- Reliability: do you get the same result twice? A good test gives similar scores when you retake it a few weeks later, and its questions agree with each other.
- Validity: does it measure what it says, and does that matter in real life? For example, do scores match how friends describe you, and do they relate to things like work habits or health over years?
Big Five scores do relate to real outcomes. A large review of long-term studies found that traits predicted mortality, divorce and job attainment about as well as socioeconomic status and cognitive ability did (Roberts et al., 2007). That is about averages across many people, not a forecast for one person.
Why psychologists lean on the Big Five
The Big Five came out of decades of studies on how people describe each other. The same five broad traits kept appearing across word lists, questionnaires and languages (Goldberg, 1990; McCrae and Costa, 1997):
- Openness: curiosity, liking new ideas and experiences.
- Conscientiousness: order, planning, following through.
- Extraversion: sociability, energy around people.
- Agreeableness: warmth, cooperation.
- Neuroticism (or its opposite, emotional stability): how strongly you react to stress.
Each trait is a scale, not a box. Most people land somewhere in the middle on most of them. For a longer walk through the model, see The Big Five explained.
Common tests, in plain facts
Named here as facts, not ranked.
| Test | What it gives you | Research base |
|---|---|---|
| NEO-PI-R / NEO-PI-3 | Big Five scores plus 30 facets | Large; used mostly by professionals, paid |
| BFI-2 | Big Five scores plus 15 facets, 60 items | Peer-reviewed (Soto and John, 2017); free for non-commercial research |
| IPIP-NEO | Big Five scores and facets, 120 or 300 items | Built from a public-domain item pool (Johnson, 2014); free online |
| HEXACO-PI-R | Six traits: the Big Five plus Honesty-Humility | Growing body of research (Ashton and Lee, 2007) |
| MBTI | One of 16 four-letter types | Very widely used; researchers have questioned how well its type split holds up on retest (Pittenger, 2005) |
| 16Personalities | One of 16 four-letter types, plus a fifth letter | Its own model; popular free online test |
| DISC | One of four work styles | Used mostly in workplace training |
| Enneagram | One of nine types | Popular; smaller body of peer-reviewed research |
Each test answers a slightly different question. A type test is built to give you a memorable label and a story about it, which many people find useful for talking about how they work. A Big Five test is built to place you on scales that research can compare. Popularity and research depth are different things, and both have their uses.
Why Ana's letters flipped
Any test that turns scores into types draws a line somewhere on each scale. If you score close to that line, a small change in mood or wording can move you to the other side, and the label changes even though you barely did. Researchers have raised this point about two-way splits in general (Pittenger, 2005), and it applies to Tipolu's five types too. That is why Tipolu shows all five scores next to the type: scores show how close to the line you were, and a label alone hides it.
Pick what you want the test for
The most accurate test depends on the job you give it. Pick a use to see what to look for.
Use A label to talk about
Look for
A type system your friends or team already know.
Keep in mind
Labels are easy to share but hide how close you were to the line.
Use Compare with research
Look for
A Big Five questionnaire with published reliability, such as the IPIP-NEO or BFI-2.
Keep in mind
Long forms take a while and ask you to rate yourself in the abstract.
Use Self-knowledge, quickly
Look for
A short test that names its model, gives scores and says what it isn't.
Keep in mind
Short and game-like formats have less research behind them so far.
Use A clinical question
Look for
A licensed professional, not an online test.
Keep in mind
No free online test, Tipolu included, is built to diagnose anything.
Where Tipolu fits
Tipolu is a self-knowledge game, not a clinical or diagnostic tool. Its five traits come from well-researched personality science, the Big Five family, but you answer by walking a short 3D story and choosing paths, not by rating statements. A validation study is planned. Until it is done, Tipolu publishes no accuracy numbers, so if you need a measure with published reliability, use one of the research questionnaires above.
What Tipolu gives you is a type, an accent, a 0 to 100 score on five traits, and a plain report on work, people and pressure, free and with no signup (Tipolu). Many people take both kinds of test and compare. The guide Personality quiz vs personality test explains how a story game sits between the two.
How to check any test in two minutes
Five questions work on any personality test, free or paid. Here is how Ana used them on the two tests she had taken.
1. Does it say what model it's based on?
Look for a named theory and named sources, not just "science-based".
Ana: the type test named its model; a fun picture quiz she'd tried didn't, which is fine for a quiz.
2. Does it publish reliability or validity data, or say plainly that it hasn't yet?
Either answer is honest. Silence is the warning sign.
Ana: she found a technical page for one test and none for the other.
3. Does it give scores, or only a type?
Scores show how close you were to the line.
Ana: her letters flipped where her scores were close to the middle.
4. Does it say what it isn't?
An online test shouldn't claim to diagnose anything.
Ana: both said they were for self-knowledge, which she liked.
5. Would people who know you recognize the result?
Friends often see some traits more clearly than you do.
Ana: she showed the result to her sister, who laughed at one line and nodded at three.
How each type tends to read a test result
Peak: Wants the verdict fast. Slow down for the scores; the close calls are where the useful detail is.
Horizon: Takes every test going. Compare scores on the same trait, not labels from different systems.
Campfire: Asks friends if it fits. Good instinct: outside views catch traits you can't see.
River: Doubts the result quietly. Check the scores before you decide it's wrong.
Root: Reads the methods page first. Look for reliability data, or a plain note that there isn't any yet.
If Ana took the test
Campfirewith a Root accentA Campfire with a Root accent fits a teacher who notices the quiet child and keeps the class running on time. Look at how close her top three scores are: 63, 58 and 55. A test that only gave her a label could easily flip between them on a different Sunday. The scores tell her why.
Ana's scores are made up to show what a result looks like.
Lu's tip: If two tests disagree about you, look at the scores, not the labels. Close scores mean both answers are a little bit true.
Questions people ask
Which personality test do psychologists use?
In research, mostly Big Five questionnaires such as the NEO-PI-R, the BFI-2 and IPIP-based tests. In clinical work, psychologists use other, specialized instruments, and those require a trained professional.
Is the MBTI accurate?
It is popular, and many people find it useful for talking about preferences. Researchers have raised concerns about its reliability on retest and about splitting people into two groups on each scale when most score near the middle (Pittenger, 2005).
Is a free test less accurate than a paid one?
Not by default. The IPIP-NEO is free and was built for research. Price tells you little; published research tells you more.
Why did I get a different result when I retook a test?
Usually because some of your scores sit near the middle, where a small change tips a label. Your mood, the day and how you read a question also move scores a little. A test that shows scores makes this easy to see.
Is the Big Five a personality type?
No. It gives you a score on five scales instead of putting you in a box. Some tests, Tipolu included, build types on top of Big Five-style traits so the result is easier to remember.
How accurate is Tipolu?
Tipolu doesn't publish accuracy numbers yet. Its traits come from the Big Five family, and a validation study is planned. Until then, treat it as a self-knowledge game and compare it with a research questionnaire if you're curious.
Sources
- Roberts, B. W., Kuncel, N. R., Shiner, R., Caspi, A., and Goldberg, L. R. (2007). The power of personality: The comparative validity of personality traits, socioeconomic status, and cognitive ability for predicting important life outcomes. Perspectives on Psychological Science, 2(4).
- Goldberg, L. R. (1990). An alternative "description of personality": The Big-Five factor structure. Journal of Personality and Social Psychology, 59(6).
- McCrae, R. R., and Costa, P. T. (1997). Personality trait structure as a human universal. American Psychologist, 52(5).
- Soto, C. J., and John, O. P. (2017). The next Big Five Inventory (BFI-2). Journal of Personality and Social Psychology, 113(1).
- Johnson, J. A. (2014). Measuring thirty facets of the Five Factor Model with a 120-item public domain inventory: Development of the IPIP-NEO-120. Journal of Research in Personality, 51.
- Ashton, M. C., and Lee, K. (2007). Empirical, theoretical, and practical advantages of the HEXACO model of personality structure. Personality and Social Psychology Review, 11(2).
- Pittenger, D. J. (2005). Cautionary comments regarding the Myers-Briggs Type Indicator. Consulting Psychology Journal: Practice and Research, 57(3).
- Tipolu, the test.
You walk a trail instead of filling a form
Tipolu is a short 3D walk. At each crossroads you pick the path you'd really take, and the companion walking with you at the end shows who you are.
12 to 20 crossroadsEveryday choices on a trail, like a market, a lake, a broken well.
Two campfire questionsShort open answers in your own words.
Your mix, not a boxA main type, an accent, and 0 to 100 scores on five traits, with a report that includes work.
Try three crossroads from the real walk
Pick the path you would really take. No right answers.
Two merchants argue loudly over a price, and a crowd gathers around them.
In an empty village you find an old workshop full of odd tools and half-built machines.
Your group is hosting a small dinner in town for friends you've made along the way.
Three forks are a guess. The full walk uses 12 to 20 of them plus two campfire questions, and shows your main type, your accent and what that means for work.
Play the free test · 5 min
Which one is walking with you?
Find out how you tend to work before you pick your next path. A short walk, 12 to 20 crossroads, and a report that includes work.
Play the free testAbout 5 minutes · no signup · free