An Unexpected Role of Local Selectivity in Social Promotion

Abstract

A selection process and a hierarchical promotion system in a dynamic model are considered as in Harrington (1998) and Garcia-Martinez (2010), where agents are "climbing the pyramid" in a rank-order contest based on the "up or out" policy. The population at any level of the hierarchy is matched in groups of n agents, and each group faces a particular environment. Agents are ranked according to the quality of their performances in each particular environment. The top k performing agents from each group are promoted. The fraction (k/n) characterizes the local selectivity of the process. The role of the degree of local selectivity in the dynamic process where agents' types differ in their expected performances is studied. For low selectivity, the selection process is not strong enough to overcome the inertia of the initial population. If selectivity increases, only the best-performing type of agent will survive. If the selectivity is increased far enough, the worst-performing type also survives, and the proportion for which they account at equilibrium increases as selectivity increases. Therefore, surprisingly, no matter how low the expected success rate of a type is, if the selection process has a high enough level of selectivity, agents of that type survive in the long run: Too much selectivity is always harmful to the best-performing type