Causal inference in the empirical sciences is based on counterfactuals. This paper presents the counterfactual account of causation in terms of Lewis's possible-world semantics, and reformulates the statistical potential outcome framework and its underlying assumptions using counterfactual...

In this paper we investigate how the expulsion of a player influences the outcome of a football match. Common sense implies a negative impact for the affected team. However, an old football myth suggests that such an expulsion might also be beneficial since it increases the team spirit as well...

When one's treatment status affects the outcomes of others, experimental data are not sufficient to identify a treatment causal impact. In order to account for peer effects in program response, we use a social network model. We estimate and validate the model on experimental data collected for...

Workers are embedded within a network of social relationships and can communicate through word-of-mouth. They can find a job either directly or through personal contacts. From this micro scenario, we derive an aggregate matching function that has the standard properties but fails to be...

We provide some of the first rigorous evidence on performance spillovers and social network in the workplace. The data we use are rather extraordinary – weekly data for rejection rates (proportion of defective output) for all weavers in a firm during a 12 months (April 2003-March 2004) period,...

In nationally representative household data from the 2008 wave of the Rural to Urban Migration in China survey, nearly two thirds of rural-urban migrants found their employment through family members, relatives, friends or acquaintances. This paper investigates why the use of social network to...

We study the mapping between labor mobility and industrial innovative activity for the population of R&D active Danish firms observed between 1999 and 2004. Our study documents a positive relationship between the number of workers who join a firm and the firm's innovative activity. This...