Ratings on 18 assessment dimensions formulated independently by assessors (psychologists and high‐level managers), consensus ratings on the same dimensions, and overall assessment ratings were collected for 329 assessees. Two hundred and seventy‐four of the assessees were promoted based on their scores obtained in the assessment process. For 240 of these we succeeded in obtaining ratings on two criterion measures over a period of four years. These criterion data were provided by their superiors who were unaware of the scores obtained in the assessment process. Multiple regression analyses were run on the data from all the assessment ratings and criterion measures. The results demonstrated a long‐term validity for the assessment center. However, we were not able to discern a consistent pattern of statistically significant differences between the predictive validities of high‐level managers and psychologists as assessors. Possibly, the type of criterion measure moderates the predictive validity of managers' and psychologists' ratings. Further, theoretical and practical implications of the findings are discussed.