Variance determines self-observer agreement on the Big Five personality traits

It is widely believed that, on those personality traits that are more visible to an external observer, two judges will reach a higher level of agreement than on those traits that are more difficult to judge. This view is challenged in the current paper, using a sample of 672 participants in the age range of 18–87 years who described their own personality and were judged by an external observer who knew them well, using the NEO PI-3 questionnaire (McCrae, Costa, & Martin, 2005). The self-observer agreement on the 30 personality subscales varied from .38 (O3: Feelings) to .57 (E5: Excitement Seeking). Approximately one-half of the variance in the agreement level was explained by the standard deviation of the sum scores of these subscales: self-observer agreement was higher in the subscales on which individual differences were larger. After correction for the range of variance, differences in self-observer agreement substantially diminished. It is proposed that judges who know each other well reach an approximately equal level of agreement on all the Big Five personality traits.