TRUE-NORTH · FFM-INVENTORY · REV. 2026

Five-Factor Model · Self-Report Inventory

Big Five Personality Inventory

Two validated, public-domain instruments from the International Personality Item Pool (IPIP): a short screening form and a full facet-level inventory — each translated into a familiar 4-letter type, with an explicit confidence rating on every dimension.

REVIEWED BY Camille G., Founder of Loch Ness Paris · LAST UPDATED SEPTEMBER 18, 2026

Instrument Family
IPIP (Goldberg, 1992)
Construct
Big Five (OCEAN)
Response Format
5-Point Likert Scale
Instructions. The following statements describe people's behaviours. Select how accurately each statement describes you generally, not as you wish to be. Most online MBTI-style instruments use 4–8 items per dimension and do not report measurement uncertainty; this inventory uses validated public-domain item sets and reports a confidence flag on every dimension.
Screening Form
IPIP-50
10 ITEMS × 5 DOMAINS · ~7 MIN
Free

The standard 50-item Big Five Factor Markers (Goldberg, 1992). Reports your 4-letter type across the five broad domains, with a confidence rating on each.

  • 5 broad domain scores
  • Confidence rating per dimension
  • Results by email
IPIP-NEO-120
120 ITEMS × 30 FACETS · ~25 MIN
$9 one-time

The full-length inventory (Johnson, 2014), reporting all 30 underlying facets across the five domains — the same structure used in the commercial NEO-PI-R.

  • 30 facet-level sub-scores
  • All 5 domain scores
  • Printable PDF-style report

Methodological Note

Independent research on the standard MBTI (Pittenger, 2005) found that 35 to 50 percent or more of respondents receive a different four-letter type when retested within weeks. This instability is well documented: MBTI-style scoring forces continuous traits into a hard binary cutoff, so respondents scoring near the midpoint on a dimension can shift to the opposite letter from measurement noise alone.

This inventory measures the five empirically-derived Big Five domains using the IPIP-50 (Goldberg, 1992) — a public-domain instrument with ten items per domain — then translates the result into a familiar 4-letter label. Any domain scoring between 45% and 55% is flagged as a genuine indeterminate result rather than being silently resolved into a confident-looking letter.

Dimension Correspondence

A fifth domain, Emotional Stability (the inverse of Neuroticism), is also reported. This domain has no MBTI equivalent — a commonly cited limitation of Myers-Briggs theory.

Limitations

Frequently Asked Questions

Is this the official MBTI assessment?

No. This uses the public-domain IPIP-50, translated into a familiar 4-letter label. It is not licensed or administered by the Myers-Briggs Company.

What is the difference between the IPIP-50 and the IPIP-NEO-120?

The IPIP-50 measures 5 broad domains with 10 items each. The IPIP-NEO-120 measures the same domains at facet level — 30 facets in total — using 120 items.

Why do MBTI-style tests give different results each time?

Research shows 35–50%+ of respondents receive a different type on retest within weeks, primarily because scores near the midpoint are resolved into one letter or the other essentially at random.

What is the IPIP?

The International Personality Item Pool is a public-domain set of personality items developed by psychologist Lewis Goldberg, freely usable for any purpose without permission.

Is my data stored anywhere?

All scoring occurs in the browser. The email used to unlock the free report is only used to send that report — see our legal notice.

About This Assessment

Developed and maintained by Camille G., founder of Loch Ness Paris. This page summarizes peer-reviewed psychometric literature (see Sources below); it is not itself original research, and True North is an independent implementation of public-domain instruments — not a clinical or diagnostic tool.

Disclosure. The free IPIP-50 result requires an email address, used only to send that result. The IPIP-NEO-120 report is a paid, one-time purchase.

Sources & References

  1. Goldberg, L. R. (1992). The development of markers for the Big-Five factor structure. Psychological Assessment, 4(1), 26–42. https://doi.org/10.1037/1040-3590.4.1.26
  2. Pittenger, D. J. (2005). Cautionary comments regarding the Myers-Briggs Type Indicator. Consulting Psychology Journal: Practice and Research, 57(3), 210–221. https://doi.org/10.1037/1065-9293.57.3.210
  3. 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, 78–89. https://doi.org/10.1016/j.jrp.2014.05.003
  4. McCrae, R. R., & Costa, P. T. (1989). Reinterpreting the Myers-Briggs Type Indicator from the perspective of the five-factor model of personality. Journal of Personality, 57(1), 17–40.
  5. International Personality Item Pool (IPIP) — a scientific collaboratory for the development of advanced measures of personality and other individual differences (ipip.ori.org).