The NEO PI-R and the IPIP-NEO

The Revised NEO Personality Inventory (NEO PI-R) was developed by Paul Costa and Robert McCrae from the 1970s through to the 2000s. This is a version of the big 5 which subdivides each trait into six facets. This has become one of the most popular and influential renderings of the big 5 system and it is this model (along with its descendants) that you are most likely to encounter when researching big 5 traits. This is a proprietary inventory which means that some kind of remuneration must be paid to the copyright owners whenever the test is used. The International Personality Item Pool (IPIP) organisation developed their own version of the NEO (and of numerous other personality inventories) in response to a demand for public domain versions of inventories like the NEO PI-R. If you have ever taken a free Big 5 test online that presented your results in the form of six facets per trait then that test was probably based on the IPIP-NEO. Because this version is free to redistribute, it is (an edited) version of the NEO that is available on this wiki. Likewise, when people discuss the NEO facets, they will typically use the facet names from the IPIP version rather than from the official NEO PI-R version.

The thirty facets (6 x 5) listed in either system are essentially the same. The IPIP can unofficially be regarded as a public domain "copy" of the NEO PI-R and the two systems can be thought of as interchangeable and essentially identical. Due to the similarity of these 2 versions, it is not necessary to specify which you are using or referring to, you can simply use the label "NEO" to refer to either.

The NEO is not necessarily the best, the most accurate or the conclusive version of the big 5, it is simply the most widely used. It is also worth remembering that the big 5 (unlike most other personality systems) is based on science and so is liable to change and be updated as more research is done and as new data and new findings demand that we change our conceptions and definitions. 

The following pages will describe each of the thirty facets by comparing the differences between people who score high versus people who score low for a given facet. This does not mean that the world is divided into people who score either high or low for each facet with no middle ground (e.g. very imaginative people, completely unimaginative people and no one who is partially imaginative). Each facet is describing a spectrum along which we orient ourselves by understanding the lowest and highest positions on the spectrum. When thinking about where people place on the spectrum for each facet it is helpful to have numerical and/or verbal scales with which to label people. The following five point scale is probably the most easy and practical way to score a person's facets:

1: Very Low
2: Low
3: Moderate
4: High
5: Very High

When reading the following pages, for each facet try to consider where you or someone you know might fall on this five point scale. This is the quickest and easiest way to grasp how the NEO works and how to use it to evaluate personality.