The authors investigated temporal trends in the validity of an assessment center consisting of a group discussion and an analysis presentation exercise for predicting career advancement as measured by average salary growth over a 7-year period in a sample of 679 academic graduates. The validity of the overall assessment rating for persons with tenure of 7 years, corrected for initial differences in starting salaries and restriction in range, was .39. There was a considerable time variation in the validity of both the overall assessment rating and the assessment center dimensions. In accordance with findings from research in managerial effectiveness and development, the interpersonal effectiveness dimension became valid only after a number of years, whereas the firmness dimension was predictive in the whole period and increased with time. For comparison, validity trends for 2 types of interviews and a mental test were also studied.