Promotion dynamics the Peter Principle: Incumbents vs. external hires

The "Peter Principle" (Peter and Hull, 1969; Fairburn and Malcomson, 2001; Lazear, 2004) suggests that individuals are "promoted to their level of incompetence". A corollary of the "Peter Principle" prediction is that external hires should have an advantage when competing with incumbents for a higher position. Using five years of personnel records from a single large U.S. corporation, this paper contributes to the literature on internal labor markets and intra-firm job mobility by testing this prediction for career advancement. Results support the idea of differences in promotion dynamics among incumbents and external hires, since past career advancement within the firm result in a lower probability of subsequent promotion, even after controlling for workers' heterogeneity and tenure on the current job. The advantage for external hires does not hold once other job changes (lateral transfers, task reorganizations) are considered, highlighting that promotions are a very different job placement mechanism than transfers. Overall, the evidence points out towards declining performance following promotion, as opposed to alternative competing hypothesis of probation placement or "handicapping" external candidates.