Acquaintanceship and self/observer agreement in personality judgment

•Accuracy of personality judgment increases as acquaintanceship increases.•HEXACO X, E, and O show higher agreement at low acquaintanceship than do C, A, and H.•Accuracy increase for C is steep across acquaintanceship levels.•Personality facets show different accuracy trends across acquaintance levels.

Self/observer agreement on HEXACO-PI-R scale scores was examined as a function of observers' subjective ratings of acquaintanceship. For each participant (N = 2199), personality self-reports were obtained along with observer reports from a friend. Each factor-level scale displayed a different pattern of upward accuracy (agreement) trends in personality judgment. Self/observer agreement for Extraversion, Emotionality, and Openness was noticeably stronger at lower acquaintanceship than that for Conscientiousness, Agreeableness, and Honesty-Humility. Conscientiousness showed a steep upward accuracy trend across acquaintanceship levels, reaching a level of accuracy comparable to that of Extraversion and Emotionality. Self/observer agreement for Honesty-Humility and Agreeableness showed slower upward trends than that of Conscientiousness. In several cases, facet-level traits within the same broad factor differed in their accuracy trends.