Before believing what a personality test tells you, one question is worth asking: is that result reliable? The answer is not a blanket yes or no. It depends on how the test was built, and science has precise criteria for judging it. Knowing them lets you tell what a result is worth, yours or anyone’s.
This article explains what “reliable” means for a personality test, the two criteria that matter, and where the Big Five stands against them.
Reliability: Getting the Same Result Twice
The first criterion is test-retest reliability. A reliable test gives similar results when you take it again a few months later, provided nothing important has changed in you in the meantime. This is the baseline: if a test describes you one way today and very differently in three months, for no reason, it measures nothing stable.
This reliability is quantified. Researchers compare the results of the same group of people tested twice, and derive an index between 0 and 1. The closer to 1, the more reliable the test. For the Big Five, this index generally sits around 0.80, with variation across dimensions and studies, which is considered high for a psychological measure. It is one of the reasons this model serves as a reference in research.
Validity: Measuring What It Claims to Measure
The second criterion is validity. A valid test truly measures what it claims, and its results show up in people’s real behavior. A test can be reliable without being valid: it would then always give the same result, but a result that corresponds to nothing.
Validity is checked by comparing a test’s scores against independent observations. When a person scores high on a dimension, is that tendency found in their life, in how those close to them see them, in their choices? For the Big Five, many studies have established these correspondences, and the five dimensions turn up across very different cultures and languages. That regularity is a strong sign of validity.
Two questions to judge a test: does it give the same result if you retake it, and does that result hold up in your real life? Reliability and validity. A serious test answers yes to both.
What Reliability Does Not Guarantee
A reliable test remains a tool, not a verdict. Even well built, it describes tendencies, not a destiny. Your results can shift slowly over the course of your life, and a score confines you to nothing. Reliability guarantees that the measure is solid, not that it says everything about you.
Nor does it replace your own reading. A reliable result is a starting point for observing yourself, discussing, adding nuance, not a label to wear without distance.
It is in this spirit that Solivalis relies on the Big Five, also called the OCEAN model, a model chosen precisely for its solidity. You can see what a reliable measure gives on your own profile by taking the test for free, or first understand why this model serves as a reference.
