Working Paper No. 617

Who's Who in Crime Networks. Wanted: The Key Player

Publicerad: March 29, 2004Antal sidor: 29Nyckelord: Social Networks; Crime; Centrality Measures; Key Group; PoliciesJEL-koder: A14; C72; K42

Who's Who in Crime Networks. Wanted: The Key Player Coralio Ballester, Antoni Calvó-Armengol and Yves Zenou


Criminals are embedded in a network of relationships. Social ties among criminals are modeled by means of a graph where criminals compete for a booty and benefit from local interactions with their neighbours. Each criminal decides in a non-cooperative way how much crime effort he will exert. We show that the Nash equilibrium crime effort of each individual is proportional to his equilibrium Bonacich-centrality in the network, thus establishing a bridge to the sociology literature on social networks. We then analyze a policy that consists of finding and getting rid of the key player, that is, the criminal who, once removed, leads to the maximum reduction in aggregate crime. We provide a geometric characterization of the key player identified with an optimal inter-centrality measure, which takes into account both a player's centrality and his contribution to the centrality of the others. We also provide a geometric characterization of the key group, which generalizes the key player for a group of criminals of a given size. We finally endogeneize the crime participation decision, resulting in a key player policy, which effectiveness depends on the outside opportunities available to criminals.

 

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Den här boken, författad av Gabriel Heller Sahlgren och Nima Sanadaji, spårar rötterna till den svenska skolans problem via en djupdykning i forskning och modern historia. På 1800-talet slog den progressiva utbildningsfilosofin igenom, med fokus på glädje, elevdemokrati och elevledd undervisning. Problemet var bara att den nya pedagogiken inte fungerade som det var tänkt. Forskningen tyder inte på att elever lär sig mer när de har roligt.

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