It began as a study of ageing
In the 1970s Costa and McCrae were studying how personality changes with age, using inventories in the Normative Aging Study. Comparing the rival factor-analytic theories of the day, they found far more agreement at the level of broad factors than narrow ones.8
Neuroticism and Extraversion were already recognised as the "Big Two". In 1978 Costa and McCrae argued that Openness to Experience was a third major dimension.2
Domains, then facets
Pick an edition to see which traits it measured and how finely.
Agreeableness and Conscientiousness were added as broad scales, but only N, E and O had six facet scales each. Agreeableness was a single 18-item scale.6
Each small block is one facet scale. Item counts are shown only where a source gives them.
You rate yourself, and someone else rates you
Strong domains, looser facets
Internal consistency reported in the manual, from a job-performance sample of 1,539 people. The facet scales ranged from .56 to .81, which the authors attribute to each facet having only eight items.7
References
- [1]Wikipedia contributors. Revised NEO Personality Inventory (accessed 30 Sept 2026).en.wikipedia.org
- [2]Costa, P. T., & McCrae, R. R. (1995). Domains and facets: hierarchical personality assessment using the Revised NEO Personality Inventory. Journal of Personality Assessment (PDF).jenni.uchicago.edu
- [3]The NEO Personality Inventory test. Psychometric Success (2026).psychometric-success.com
- [4]NEO Personality Inventory-Revised (NEO PI-R), with references to the 1985, 1989 and 1992 manuals. Society for Judgment and Decision Making, DMIDI.sjdm.org
- [5]A more readable Revised NEO Personality Inventory. Journal of Personality Assessment, 84(3). Taylor & Francis (PDF).tandfonline.com
- [6]McCrae, R. R., & Costa, P. T. A contemplated revision of the NEO Five-Factor Inventory. University of Illinois course materials (PDF).cda.psych.uiuc.edu
- [7]Revised NEO Personality Inventory. Psynso (2017).psynso.com
- [8]Revised NEO Personality Inventory. OMICS Group research encyclopedia.research.omicsgroup.org
- [9]NEO PI-R. In Peace Officer Psychological Screening Manual. California Commission on POST (PDF).post.ca.gov
- [10]Validation of the Greek translation of the NEO-PI-3 (2014). Annals of General Psychiatry. Springer.link.springer.com
Related historical tests
Cattell split personality into 16 factors. Costa and McCrae noticed that such rival systems agreed far more at the level of broad factors, which led them to the five.
The five-factor model the NEO-PI-R was designed to put into practice. The NEO line is the best-known questionnaire built on it.
Trait anxiety sits close to what the NEO calls Neuroticism. Both ask how you generally are rather than how you feel right now.
Another self-report questionnaire, but for a clinical condition. The NEO-PI-R was intended for adults without overt psychopathology.
An early scale completed from an informant's reports. The NEO's Form R brings the same observer approach to personality.
The TAT asks people to tell stories about pictures, which are then interpreted. The NEO asks direct statements on a rating scale, the opposite approach.