Key Player Policies When Contextual Effects Matter

We consider a model where the criminal decision of each individual is affected by not only her own characteristics, but also by the characteristics of her friends (contextual effects). We determine who the key player is, i.e. the criminal who once removed generates the highest reduction in total crime in the network. We generalize the intercentrality measure proposed by Ballester et al. (2006) by taking into account the change in contextual effects following the removal of the key player. We also provide an example that shows how the new formula can be calculated in practice.