Why are moderators of self-other agreement difficult to establish?

• Two large samples (N = 11,096) completed NEO-PI-3 and HEXACO-PI-R.
• Age and sex of participants and length of acquaintance had no significant effect.
• Sufficiently good agreement between self- and other-judgments was reached.
• Judging another person’s personality is an easy task.
• Perhaps only the closeness of the target-judge relationship moderates agreement.

Agreement between the self and other rated personality profiles was studied in two samples involving 11,096 speakers of two languages, Dutch and Estonian, who completed two different personality questionnaires, the NEO-PI-3 and HEXACO-PI-R. An outstanding agreement was achieved in the most occasions: in only 4–6% of dyadic pairs was the correlation between two randomly paired profiles higher than the actually observed correlation between true pairs. As in previous studies, we found that age and sex of participants and length of acquaintance had no significant effect on the level of self-other agreement. However, intimate knowledge helped married and unmarried couples in both samples be more accurate in their personality judgments; family members, in turn, had knowledge that made them more accurate than two people who were just acquaintances or friends. We believe that these outcomes can be explained by the contention that the judgment of another’s personality is a relatively simple task, which is accomplishable for most people most of the time. In other words, because judging another person’s personality is an easy task, we are not able to determine “good targets,” “good judges,” or “good traits.” Perhaps it is only “good information” which determines the closeness of the target-judge relationship, and which has a small but reliable impact on the level of self-other agreement. This explains why it is so difficult to find individual differences in the ability to judge another person’s personality.