An Overview of the NEO-PI-R and Its Structure
The NEO-PI-R, or NEO Personality Inventory-Revised, is a comprehensive personality inventory based on the Big Five model, published by Paul Costa Jr. and Robert McCrae in 1992. The letters NEO originally derived from the initials of Neuroticism, Extraversion and Openness, but the revised edition measures all five factors, adding Agreeableness and Conscientiousness to the original three. The instrument consists of 240 items in total, with 48 items assigned to each factor, made up of six subscales of eight items apiece. Responses are given on a five-point Likert scale running from strong disagreement to strong agreement, and administration takes approximately 35 to 45 minutes. Two versions exist: a self-report form (Form S) and an observer-rating form (Form R). The degree of agreement between the two constitutes important evidence supporting the validity of personality measurement in general.
Thirty Facets and the Precision They Allow
The most distinctive feature of the NEO-PI-R is that each of the five broad factors is subdivided into six subscales, called facets, which refines the description of personality considerably. Extraversion, for example, divides into warmth, gregariousness, assertiveness, activity, excitement seeking and positive emotions. This structure makes it possible to distinguish, among people who are all simply high in extraversion, the sociable type who does not seek stimulation from the stimulation-seeking type who is nonetheless low in warmth. This precision matters most when two people's factor-level scores look almost identical and yet the way they actually spend time together does not mesh. If both partners are high in extraversion but one is characterised by gregariousness, a preference for large gatherings, and the other by assertiveness in the sense of leadership, subtle friction can arise over how they spend their time in social settings.
Reliability, Validity and Practical Considerations
The NEO-PI-R is a psychometrically high-quality instrument. Internal consistency, expressed as Cronbach's alpha, falls in the range of .86 to .92 at the factor level and .56 to .81 at the facet level. Test-retest reliability has been reported at .63 to .83 over a six-year interval, which reflects the stability of personality during adulthood. Construct validity is supported by correlations with other personality measures, by correspondence with behavioural observation data, and by predictive power for life outcomes such as occupational success, health behaviour and relationship satisfaction. There are practical drawbacks, however. A length of 240 items is tolerable in research settings but imposes a heavy burden in clinical and applied ones. For that reason, the shortened NEO-FFI with 60 items and the still more convenient BFI-2, also 60 items, have been developed. A short form is easier to sit through, but it cannot separate out the thirty facets. If the questionnaire you have answered runs to around 60 items, treat its output as reaching the level of the five broad factors and no further. Reading facet-level differences calls for one of the longer instruments, normally administered by a trained practitioner. A Japanese-language version was standardised by Shimonaka and colleagues in 1999, with reliability and validity confirmed in Japanese samples.