IPIP stands for the International Personality Item Pool. It is a free collection of more than 3,000 personality statements, not a single test. Researchers pick statements from it to build questionnaires, such as the IPIP-50 and the IPIP-NEO-120.
What is the International Personality Item Pool?
The pool is a public library of personality statements, called items, and the scales built from them. The psychologist Lewis R. Goldberg wrote most of the items. The website launched in 1998 with the help of a grant from the National Institute of Mental Health (NIMH). The Oregon Research Institute hosts it at ipip.ori.org.
Anyone can copy, translate or use the items for free, for any purpose. Goldberg developed the pool to support personality research in many settings. The project paper describes a public item pool that researchers can test, compare and adapt. The site also publishes scoring keys and cautions about reading one person's scores.
Is the IPIP a test?
No. The IPIP is the pool, and the tests are questionnaires built from it. Saying you took "the IPIP" leaves out the most important detail. Different questionnaires use different items from the same pool, and three well-known IPIP questionnaires measure the Big Five personality traits:
| Questionnaire | Items | What it scores |
|---|---|---|
| IPIP-50 | 50 | Five broad traits |
| IPIP-NEO-120 | 120 | Five broad traits and 30 facets |
| IPIP-NEO-300 | 300 | Five broad traits and 30 facets |
The IPIP-50 uses Goldberg's 50 Big-Five Factor Markers, ten for each trait. The IPIP-NEO-120 uses a different set of 120 items, four for each of its 30 facets. Their trait names overlap, but their items and score ranges differ. You cannot convert a score from one into the other, or borrow its evidence, bands or norms.
The 10-item TIPI often appears beside these tests, but it is not an IPIP scale. Gosling and colleagues developed it separately, for settings where a longer Big Five measure would not fit.
What are the IPIP-NEO-120 and IPIP-NEO-300?
They are IPIP versions of the NEO PI-R, a commercial questionnaire by Paul Costa and Robert McCrae. Both measure the same five broad traits and 30 narrower facets. Goldberg's 300-item version was one of the first IPIP measures. John A. Johnson later chose 120 of its items for the shorter version (Johnson, 2014).
Johnson's IPIP-NEO site offers both versions free. It says the 300-item version takes most people 30 to 40 minutes, and the shorter one 10 to 20. Johnson adds that the longer original gives somewhat more reliable and valid results. Survey Doctor offers the IPIP-NEO-120, not the 300-item version.
Neither version is the NEO PI-R itself. The IPIP says its scales are not identical substitutes for commercial questionnaires (history of the IPIP). The items, score scales, reports and norms all differ. Do not treat an IPIP-NEO result as a free copy of a NEO report, or convert scores between them.
What do IPIP scores tell you?
An IPIP Big Five test gives a separate score for each trait, not one overall score. The traits measure different things, so adding them together gives a number with no meaning. A higher total is not a better personality. A change in a trait over time is not progress or decline either, because no trait has a good direction.
Each score is a raw score: the sum or average of your answers, after some answers are reversed. A raw score is not a percentile, which needs a comparison group. The IPIP publishes no norms, and its norms page warns that most ready-made norms mislead.
The scores describe broad patterns in how you see your usual behavior and preferences. Higher and lower scores describe different tendencies, and neither end is better. A profile cannot diagnose a condition or a personality disorder. It also cannot establish career fit, choose a treatment, predict an individual outcome or define a healthy personality.
Why do online IPIP results differ?
Sites that use IPIP items can still differ in item sets, wording, scoring keys, trait labels and comparison groups. Free items do not make every online result accurate. A site can use genuine IPIP items and still invent its own score bands, norms or advice.
The IPIP site describes one version that confused many people. This early online IPIP-50 called the fourth trait Neuroticism but scored it as Emotional Stability, its opposite. It also scored each trait from 0 to 40 instead of the standard 10 to 50.
Even one test name can cover two versions. The IPIP lists two different 120-item IPIP-NEO questionnaires, one by Johnson and one by Maples and colleagues. Before you compare two results, note the exact questionnaire, how it was scored and any comparison group. An adapted questionnaire is not automatically the same as the source form.
Which IPIP test should you take?
Take the IPIP-50 if five broad trait scores answer your question. Take the IPIP-NEO-120 if the 30 narrower facets matter too. Use the TIPI only when brevity is essential, because two items per trait give less detail.
The IPIP-50 and IPIP-NEO-120 comparison explains the choice in more detail. After you finish, the score guides for the IPIP-50 and the IPIP-NEO-120 explain what each trait score describes.