To expand our knowledge of personality assessment, this study connects research and theory related to two common selection methods: assessment centers (ACs) and personality inventories. We examine the validity of personality-based AC ratings within a multi-method framework. Drawing from the self-other knowledge asymmetry model (Vazire, 2010), we propose that AC ratings are suited to capture personality traits that are observable in social interactions, whereas other methods (i.e., self-ratings) are useful to assess more internal traits. We obtained data from two personality-based ACs, self-and other-rated personality inventories, and supervisor ratings of job performance.Confirmatory factor analyses indicated that personalitybased AC ratings reflected the Big Five traits. Consistent with the self-other knowledge asymmetry model, AC ratings of more observable personality traits (Extraversion, Agreeableness, and Intellect/Openness) were correlated with inventory-based measures of these traits. AC ratings demonstrated incremental validity in predicting job performance over inventory-based personality measures for some traits (including Agreeableness, and Intellect/Openness) but self-ratings also demonstrated incremental validity over AC ratings (for Conscientiousness). This implies that differentThis is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.