The IPIP (International Personality Item Pool) website provides a copy of the IPIP representation of the NEO 30 facet form.

It also provides some information comparing IPIP NEO with official NEO. However, the information provided is incomplete for making an assessment of the psychometric properties of the test. For example, I'd like to know about: (a) how items were chosen; (b) what was the sample size and characteristics used to generate the comparative correlation information provided; and (c) what is the factor structure of the IPIP NEO.

Thus, my questions:

  • Where can I find information on how the IPIP NEO (30 facet version) was developed?
  • What studies have examined the psychometric properties of the IPIP NEO (30 facet version) both in absolute terms and relative to the official NEO?
  • $\begingroup$ Did you asked the author(s)? I also tried to mimic official NEO-PI with IPIP but also couldnt find norms. I asked on faculty but they told me that norms does not exist. $\endgroup$
    – ICanFeelIt
    Jul 26 '13 at 13:56

The table found at your second link (comparing the IPIP NEO and official NEO) seems to have come from this paper by Goldberg (1999): http://projects.ori.org/lrg/PDFs_papers/A%20broad-bandwidth%20inventory.pdf. This paper discusses the generation of the IPIP items as well as the sample it was originally administered in. A 2006 paper (also by Goldberg) provides additional information on IPIP development:

Unfortunately, I was unable to locate information on the factor structure of the IPIP NEO 30 facet form, only the IPIP 50-item FFM (Ehrhart, Roesch, Ehrhart, & Kilian, 2008), which seems to be a different measure (http://ipip.ori.org/newFinding_Labeling_IPIP_Scales.htm).

Ehrhart, K. H., Roesch, S. C., Ehrhart, M. G., & Kilian, B. (2008). A test of the factor structure equivalence of the 50-Item IPIP Five-Factor Model Measure across gender and ethnic groups. Journal of Personality Assessment, 90(5), 507–516.

Goldberg, L. A., Johnson, J. A., Hogan, R. , Ashton, M. C., Cloninger, & Gough, H. G. (2006). The international personality item pool and the future of public-domain personality measures. Journal of Research in Personality, 40, 84–96.


I know that the question is old, but it is still relevant so I will attempt to answer.

In the meantime Johnson has developed a 120-item version of the IPIP-NEO. The development is described in detail here:

Johnson, J. A. (2014). Measuring thirty facets of the Five Factor Model with a 120-item public domain inventory: Development of the IPIP-NEO-120. Journal of Research in Personality, 51, 78–89. https://doi.org/10/bc99

And there is an additional validation study here:

Kajonius, P. J., & Johnson, J. A. (2019). Assessing the Structure of the Five Factor Model of Personality (IPIP-NEO-120) in the Public Domain. Europe’s Journal of Psychology, 15(2), 260–275. https://doi.org/10/gh8gk3

I can definitely recommend reading both papers. While the IPIP-NEO-120 has some psychometric problems, the NEO-PI-R is also far from perfect. I believe IPIP is the future due to its non-proprietary nature.


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