Network Effects Cause Interference In State Legislature Experiments

Recent work on legislative politics has documented complex patterns of interaction and collaboration through network analysis. Field experiments, a growing approach in state legislatures for causal identification, face unique challenges when social networks exist.

Data & Methods

• Use recently developed methods that account for interference caused by network effects
• Specify spillover models defining how legislators influence each other
• Identify the precise network structure facilitating treatment spread
• Analyze data from two previously published field experiments on state legislatures

Key Findings

• Existing research shows mixed evidence for persistent spillover effects in legislative settings.
• Networked social interaction demonstrably affects outcomes, requiring special consideration beyond standard assumptions.

Why It Matters

These findings highlight the necessity of incorporating network considerations into experimental designs and analyses studying state legislatures. The replication analyses demonstrate practical ways to test for interference using advanced techniques.