Structural Redundancy and Multiplicity within Networks of US Corporate Directors

The argument of this paper is that social ties beyond the boardroom matter. At the structural level, social ties from non-profit foundations, cultural organizations, university boards, policy planning organizations, and private social clubs add unique ties to those established by interlocking directorates. In addition, the multiple configurations of these social affiliations increase the centrality and reduce the social distance among the corporate directors. Although visualizations of these social networks underscore the changing roles these extra-corporate ties play in uniting corporate directors, they cannot precisely capture the unique effects of ties created by social affiliations outside the boardroom. Utilizing the concepts of structural redundancy and multiplicity, the paper describes the unique contribution each set of ties makes in constructing the social mosaic of corporate America during the second half of the 20th century. The results indicate a dramatic reduction in the role private clubs play in supplementing corporate ties, and an equally significant rise in the importance of social ties generated by policy planning organizations.