In general, correlations between assessment centre (AC) ratings and personality inventories are low. In this paper, we examine three method factors that may be responsible for these low correlations: differences in (i) rating source (other versus self), (ii) rating domain (general versus specific), and (iii) rating format (multi- versus single item). This study tests whether these three factors diminish correlations between AC exercise ratings and external indicators of similar dimensions. Ratings of personality and performance were combined in an analytical framework following a 2 × 2 × 2 (source, domain, format) completely crossed, within subjects design. Results showed partial support for the influence of each of the three method factors. Implications for future research are discussed. Copyright © 2004 John Wiley & Sons, Ltd.