Board Interlock Network Analysis

Board interlock network analysis treats the corporate economy as a network in which two firms are tied whenever they share a director, and studies how these interlocking directorates channel information, influence, and the diffusion of practices among companies. Mizruchi's 1996 Annual Review of Sociology synthesis crystallized the field, distinguishing the determinants of interlocks from their consequences and cataloguing the mechanisms — collusion, cooptation and monitoring, legitimacy, career advancement, and social cohesion — that interlocks have been argued to serve. Davis's 1991 study of how the poison-pill takeover defense spread through the board network gave the perspective its canonical demonstration that corporate practices diffuse along director ties. The method combines two-mode-to-one-mode network construction with positional metrics and diffusion modeling.