Assessing the extent to which network structure causes people to be perceived as a leader

Social network experiments provide a powerful framework for identifying causal network effects but also allow a specific form of network endogeneity. Random assignment eliminates the correlation between individual differences and treatment assignment but not between individual differences and treatment response. Individual differences can shape how participants enact their assigned networks. We use data from three networks to demonstrate an underappreciated approach for estimating causal network effects in the presence of endogeneity. The pre-experiment network captures individual differences, the treatment network defines the assigned structure, and the behavioral network reflects the interactions that occur during the experiment. Because the treatment network is exogenously assigned, it can serve as an instrument for the behavioral network, isolating the causal component of behavioral network effects. Using data from a coordination experiment, we estimate the causal effect of brokerage in the behavioral network on an important team outcome: perceived leadership. We also examine the influence of pre-experiment networks, finding that individuals who enter with closed networks sometimes emerge as brokers. The result shows that behavioral networks form through interdependent choices and interactions among multiple individuals and that endogenous network structures can generate effects beyond the control or intentions of any single individual.