The players named in the Mitchell report arrange naturally into a social network, based on the report's meticulous detail of how the players introduced their friends and teammates to former Mets batboy turned trainer Kirk Radomski. As players moved from team to team, news of Radomski's access to steroids and human growth hormone expanded rapidly, until he was dealing with dozens of clients at once.

The players are colored according to their "connectedness" to the rest of the network, an index that measures how closely each individual is related to all other players. (Sociologists refer to this measure as centrality.) While Radomski is the most central figure, several other key players held the network together: David Segui, David Justice, Jason Grimsley, Denny Neagle, Chris Donnels, and Todd Hundley. Conversely, Miguel Tejada is the most distant from the center, with three intermediaries between himself and the original contact with Radomski.

The software package that we used to build the network, SocialAction, automatically identified subgroups within the network using a statistical clustering algorithm. These subgroups—"Riggs Crew," "Segui Crew," etc.—are represented in the chart with gray circles. Although we did not feed the algorithm any team information, the SocialAction software was able to identify teammate groups based solely on a collection of links between individuals.