IPIP NEO Personality Inventory

NEO Personality Inventory


The Revised NEO Personality Inventory (NEO PI-R) is a psychological test that assesses an individual on five dimensions of personality (Big 5 personality traits). These traits are openness, conscientiousness, extraversion, agreeableness, and neuroticism. In addition, the inventory also reports on six subcategories (the so called facets) of each Big 5 personality trait.


Development of the NEO Personality Inventory began in 1978 when Costa and McCrae published their first inventory. After, the researchers published three updated versions of the inventory in 1985, 1992, and 2005. These revised tests featured updated vocabulary. Such a revision was necessary to help adults of any education level and children to understand the essence of questions.

Goldberg’s Item Pool

Lewis Goldberg created the International Personality Item Pool (IPIP) as a first step towards using an open-source methodology in creating a measure for personality. Accordingly, the IPIP is a scientific collaboratory for the development of advanced measures of personality and individual differences. It includes over 3,000 items and over 250 scales constructed from the items.

The items and scales are in the public domain. It means that one can copy, edit, translate, or use them for any purpose without asking permission and without paying a fee. The IPIP is a collection of assessment items (or questions) which assesses the broad variety of possible differences between individuals. As a matter of fact, various experimental and statistical methods allowed Goldberg to accurately chose questions for the factors and sub-facets of the NEO-PI-R. Thus, the IPIP-NEO was born.

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Structure of the IPIP NEO

The standard IPIP NEO test consists of 300 questions. Its smaller versions are the 120 question IPIP NEO 120 and the 60 question IPIP NEO 60.  Responses to each question are given on a 5-point Likert scale. The responses range from 0 to 4, from “very inaccurate” (0) to “very accurate” (4). Basically, the reversed scale is used for instances where the factor key indicates a negative symbol (-). The IPIP-NEO consists of 30 sets of 10 items. The IPIP-NEO-120 has 30 sets of 4 items and the IPIP-NEO-60 has 30 sets of 2 items. Thus, the highest score possible in facet is 40, 16, and 8 respectfully. As each factor of personality consists of 6 facets, the highest score possible in any factor is 240, 96, and 48 respectively. Accordingly, these results are calculated and represented as a percentage value.

Use of the IPIP NEO

The IPIP NEO is considered to be a reliable and valid measure of personality. That is why it is widely used in research and professional settings to assess personality and make informed decisions. Another key point is understanding an individual’s personality traits that can be important in a variety of contexts. This can include, without limitation, prediction of behavior and possible response to different situations, as well as assessment of suitability for certain tasks or roles. As can be seen, the IPIP NEO helps to study the relationship between personality and various outcomes, such as mental health, job performance, and relationship satisfaction. For example, it can be used in organizational psychology to assess job candidates (their fit for both the job and corporate culture) or to evaluate the personality traits of employees.

Please read our dedicated articles to learn more about individual personality traits of the IPIP NEO and their facets: openness to experience, conscientiousness, extraversion, agreeableness, neuroticism.

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