Why do top management teams look the way they do? A multilevel exploration of the antecedents of TMT heterogeneity

While individual-level social psychological processes may promote top management team (TMT) homogeneity, a number of organizational and environmental factors pose requirements for increasing TMT heterogeneity. These opposing mechanisms lead to different predictions regarding the outcome of the TMT selection process. This article investigates the interactions between the different level factors influencing TMT heterogeneity in order to determine under what conditions pressures towards heterogeneity prevail over the tendency towards homosocial reproduction. Based on a panel dataset of 165 Swiss listed companies, the results of hierarchical linear model (HLM) analyses provide support for attraction-selection-attrition (ASA) and similarity-attraction tendencies. Newly appointed TMT members were more likely to be similar to the rest of the team when the prior degree of homogeneity in the TMT was high. However, this tendency was lower in firms with a high degree of internationalization or facing dynamic industry environments. At the same time, munificent industries amplify tendencies towards TMT homogeneity.