We survey the literature on social networks by putting together the economics, sociological and physics/applied mathematics approaches, showing their similarities and differences. We expose, in particular, the two main ways of modeling network formation. While the physics/applied mathematics...

The aim of this paper is to provide a new mechanism based on social interactions explaining why minority workers have worse labor-market outcomes than majority workers. Building on Granovetter's idea that weak ties are superior to strong ties for providing support in getting a job, we develop a...

We develop two different social network models with different economic foundations. In the local-aggregate model, it is the sum of friends' efforts in some activity that affects the utility of each individual while, in the local-average model, it is costly to deviate from the average effort of...

This paper studies whether conformism behavior affects individual outcomes in crime. We present a social network model of peer effects with ex-ante heterogeneous agents and show how conformism and deterrence affect criminal activities. We then bring the model to the data by using a very detailed...

In this chapter, we provide an overview on the literature on key players in networks. We first introduce the theoretical concept of the key player, which is the agent that should be targeted by the planner so that, once removed, she will generate the highest level of reduction in total activity....

We develop an unified model embedding different behavioral mechanisms of social interactions and design a statistical model selection test to discriminate between them in empirical applications. This framework is applied to study peer effects in education and delinquent behavior for adolescents...

We develop a model where workers both choose their residential location (geographical space) and social interactions (social space). In equilibrium, we show under which condition the majority group resides close to the job center while the minority group lives far away from it. Even though the...

To better understand the way social networks operate in the labor market, we propose two simple models where individuals help each other finding a job. In the first one, job information flows between individuals having a link with each other and we show that an equilibrium with a clustering of...

We study peer effects in crime by analyzing co-offending networks. We first provide a credible estimate of peer effects in these networks equal to 0.17. This estimate implies a social multiplier of 1.2 for those individuals linked to only one co-offender and a social multiplier of 2 for those...

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...