History[edit]
In the 1970s, Paul Costa and Robert McCrae were researching how personality changed with age. Personality inventories were included in the batteries of assessments participants took in the Normative Aging Study.[1] In looking at the competing factorally analyzed trait personality theories of the day, they noticed much more agreement at the level of the higher-order factors than at the lower order factors.[2] Costa and McCrae report that they began by looking for the broad and agreed-upon traits of Neuroticism (N) and Extraversion (E), but factor analysis also led them to a third broad trait, Openness to Experience (O).[3] The original version of the inventory included only those three factors, and was published in 1978 as the Neuroticism-Extraversion-Openness Inventory (NEO-I). This version would be included in the Augmented Baltimore Longitudinal Study of Aging.[4]
From this data, Costa and McCrae recognized two more factors: Agreeableness (A) and Conscientiousness (C).[5] Accordingly, they published the first manual for the NEO that included all five of what are now known as the "Big Five" personality traits in 1985, renamed as the NEO Personality Inventory (NEO PI). In this version, "NEO" was now considered part of the name of the test and was no longer an acronym. The assessment at this time included six facet sub-scales for the three original factors (N, E, & O).[5] This naming convention continued with the third version, with the Revised NEO Personality Inventory, published in 1990,[citation needed] being referred to as NEO PI-R.
As research began to accumulate that the five factors were adequately broad to be useful, there were also calls for a more detailed view of personality.[6] In 1992 Costa and McCrae published a Revised NEO manual which included six facets for each factor (30 in total).[7]
Throughout the mid- to late-1990s, Costa and McCrae began to realize that some items on the NEO-PI-R were out-dated or too difficult to understand for participants. Research also began to show that the NEO-PI-R had the potential to be used with adolescents and children as young as 10.[8] This possibility led Costa and McCrae to administer the NEO-PI-R to over 1,900 high school students in 2002.[9] The sample yielded 48 "problem" items based on difficult comprehension of items and/or low corrected item total correlations (CITCs; i.e., the correlation between individual items and the rest of the test which essentially tells a researcher if the item belongs with the rest of the scale). Alternative items for the "problem" items were developed and administered to a new sample. Of the original 48 "problem" items, 37 were improved in terms of clarity and/or CITC. Therefore, Costa and McCrae published the latest version of the NEO Inventories, NEO-PI-3, in 2005 which included the revised 37 items