Industry: Health Data: IT Contracts sold to Health firms 1996-2005 (Computer Wire Data Base)
Treatment: Dark circles are Health clients. White circles are IT providers. Size of node represents degree centrality. Some weaker links (smaller contracts may have been filtered out). Linked providers identify a sub-contract arrangement. Thickness of the link indicates the relative size of the contract.
Commentary: Affiliated Computer Services is identified as the most central IT provider to the health industry, followed by CSC and IBM. The diagram shows that multi-sourcing is prevalent with many of the health firms buying from multiple IT providers, though often with one provider having the major contractual share.