What Is Test-Retest Reliability?
Short Answer
Test-retest reliability measures whether a test produces consistent results when the same person takes it again after an interval. High test-retest correlations (0.70+) indicate a stable, reliable assessment.
Full Answer
Test-retest reliability is one of the most straightforward ways to check if a personality test is trustworthy. Researchers administer the same test twice—typically weeks or months apart—and compare the scores. If results correlate highly (r > 0.70), the test is reliable.
For personality traits, test-retest reliability is particularly important because personality is relatively stable over time. The Big Five (OCEAN) demonstrates strong test-retest correlations of 0.80–0.90, even when taken months apart. This stability proves the test accurately captures enduring personality characteristics.
What affects test-retest reliability? Major life changes (trauma, medication, therapy), mood on testing day, and understanding of questions can slightly alter scores. However, reliable tests like JobCannon's Big Five (OCEAN) maintain consistency despite these minor variations.
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How long should I wait before retaking a test to measure test-retest reliability?▼
Typically 2–12 weeks. This interval is long enough to avoid memory effects (you don't remember exact answers) but short enough that true personality hasn't fundamentally changed. Researchers often use 4–8 weeks.
If my scores differ slightly between tests, does that mean the test is unreliable?▼
Not necessarily. Small differences (±5–10 points) are normal and expected. The test is unreliable only if scores vary dramatically or inconsistently across multiple administrations.
Why is test-retest reliability important for job seekers?▼
Employers use personality tests to assess candidates. If a test isn't reliable, it might give different results for the same candidate, making hiring decisions arbitrary. High test-retest reliability ensures fair, consistent assessments.