Bias and High-Dimensional Adjustment in Observational Studies of Peer Effects

• https://www.tandfonline.com/doi/full/10.1080/01621459.2020.1796393?scroll=top&needAccess=true
• Dean Eckles & Eytan Bakshy

Social contagion, Peer effect, Observational study, Causal inference with observational data

high-dimensional adjustment of a nonexperimental control group (660 million observations) using propensity score models produces estimates of peer effects statistically indistinguishable from those using a large randomized experiment (215 million observations).

However, even if these assump- tions are not strictly satisfied, some observational estimators, especially those that adjust for numerous or particularly relevant behavioral variables, may have relatively small bias in practice, such that the bias is small compared with other sources of error (e.g., sampling error) or is small enough to not change choices of theories or policies.