Average treatment effects in the presence of unknown interference

Understand

We investigate large-sample properties of treatment effect estimators under unknown interference in randomized experiments.

• The inferential target is a generalization of the average treatment effect estimand that marginalizes over potential spillover effects.
• We show that estimators commonly used to estimate treatment effects under no interference are consistent for the generalized estimand for several common experimental designs under limited but otherwise arbitrary and unknown interference.
• The rates of convergence depend on the rate at which the amount of interference grows and the degree to which it aligns with dependencies in treatment assignment.