[1] Both the concept and the term "facet" were introduced by Paul Costa and Robert McCrae in the first edition of the NEO-Personality Inventory (NEO-PI) Manual.
[10] Costa and McCrae originally developed facet scales for neuroticism, extraversion, and openness to experience to reflect the fact that each broader trait is composed of different aspects of personality.
[3] In contrast with Costa and McCrae's admittedly arbitrary decisions, studies guided by the Lexical hypothesis root facets in the personality language of laypeople.
[7] Using the five factor model, Gerard Saucier and Fritz Ostendorf explored each domain's facet structure through lexical studies.
In contrast, circumplex models explore personality as it is constructed in the two-dimensional space created by the intersections of these polar scales.
[8][13] Despite similarities between the Interpersonal Circle and two of the Big Five,[8] it was only later that the work of Lewis Goldberg with Dean Peabody,[14] and Willem Hofstee and Boele de Raad[8] integrated the circumplex and Five Factor models.
In place of specific facet labels, Goldberg and his colleagues use Roman numerals, and plus and minus signs corresponding to the two intersecting factors.
Corresponding NEO PI-R labels are provided in parentheses, with adjectives approximating pure Big Five traits (e.g., extraversion, neuroticism) in bold.