The basics
What is the IPIP-NEO?
A personality inventory that measures five broad domains and thirty narrower facets, built from items anyone may use freely.
The item pool behind it
The International Personality Item Pool (IPIP) is a collection of personality items that Lewis Goldberg and colleagues began assembling in the 1990s and placed in the public domain. It is hosted at ipip.ori.org, and its terms say the items and scales can be copied, edited, translated or used for any purpose without asking permission and without paying a fee. Researchers use it to build and compare scales without licence costs.
Where the “NEO” comes from
NEO stands for Neuroticism, Extraversion and Openness, the three domains that Costa and McCrae’s original inventory measured before it grew to five. Their Revised NEO Personality Inventory (NEO PI-R, 1992) measures thirty facets, six within each of the five domains. The IPIP-NEO is a separate set of public-domain items written to measure the same thirty constructs.
Five domains, thirty facets
The structure is two levels deep. The five domains are Neuroticism, Extraversion, Openness, Agreeableness and Conscientiousness, often remembered as OCEAN. Each domain splits into six facets, which describe it in finer detail. Two people with the same Extraversion score can differ in whether it comes from sociability, assertiveness or energy.
Neuroticism Neuroticism
Anxiety, Anger, Depression, Self-Consciousness, Immoderation, Vulnerability.
Extraversion Extraversion
Friendliness, Gregariousness, Assertiveness, Activity Level, Excitement-Seeking, Cheerfulness.
Openness Openness
Imagination, Artistic Interests, Emotionality, Adventurousness, Intellect, Liberalism.
Agreeableness Agreeableness
Trust, Morality, Altruism, Cooperation, Modesty, Sympathy.
Conscientiousness Conscientiousness
Self-Efficacy, Orderliness, Dutifulness, Achievement-Striving, Self-Discipline, Cautiousness.
Two versions in common use
Goldberg’s 1999 chapter published a 300-item IPIP-NEO with ten items for each facet. In 2014 John A. Johnson published a 120-item version with four items per facet, in the Journal of Research in Personality. The short form keeps the same thirty facets and takes far less time, and trades some precision at the facet level. The page on 300 items or 120 explains the trade.
How it is answered
Each item is a short first-person statement such as “Worry about things.” or “Make friends easily.” The respondent says how accurately it describes them on a five-point scale from Very Inaccurate to Very Accurate. Some items are worded in the opposite direction and are reversed when scored. Every item is shown on the facets page.
What you get back
Scores for the five domains, and for each of the thirty facets. A score tells you where you sit on a scale, and the guide to reading a score explains why that is different from a rank among other people.