Partly. 16Personalities is a free online quiz that measures five continuous traits, close to the Big Five, and then reports them as one of sixteen four-letter types borrowed from the Myers-Briggs vocabulary with a fifth letter added. The underlying scales are probably fair measures of what they measure; the type is not, because turning a position on a scale into one of two letters is unstable for the many people near the middle, and the sixteen descriptions are written to be agreed with.
What it measures
The site’s own documentation describes five scales that map onto extraversion, openness, agreeableness, conscientiousness and neuroticism, which is the Big Five under other names. That is a sensible model, and it is the reason the quiz feels like it works: the scores behind the letters are real trait scores. McCrae and Costa (1989) showed the same thing about the original Myers-Briggs scales, which correlate with four of the five factors.
What it does not
A type is a cut. Someone at the 48th percentile of extraversion and someone at the 52nd get different first letters and different type descriptions, though they are nearly identical. On retest, anyone near a midpoint can flip, which is the instability Pittenger (2005) documents for the original indicator and which applies to any type scheme built on continuous scores. The descriptions are flattering and general enough that most people recognise themselves in several of them, a well-known effect that makes a result feel accurate without being informative. And unlike the tests on this site, the quiz publishes no comparison sample, no reliability per scale and no items, so none of it can be checked.
Side by side
| Big Five tests on this site | 16Personalities | |
|---|---|---|
| Scales | Five traits, thirty facets, published items | Five scales, items not published |
| Result | Percentile per scale against a named sample | A four-letter type plus percentages per scale |
| Reliability | Published per scale | Not published in a form that can be checked |
| Ownership | Public domain instruments | A commercial site; the letters evoke a trademark it does not hold |
| Stability of the result | Scores move a few points between attempts | Types can flip for anyone near a midpoint |
Which to take for which purpose
For a label to share and a description to enjoy, 16Personalities is free and harmless, and its five scales are closer to the science than the letters suggest. For a measurement you can check, compare and track, take a Big Five test with published items, norms and reliability, read the percentiles rather than any label, and expect no gap between introvert and extrovert because there is none.