• Corpus ID: 237289724

Nonparametric identification is not enough, but randomized controlled trials are

@inproceedings{Aronow2021NonparametricII,
  title={Nonparametric identification is not enough, but randomized controlled trials are},
  author={Peter M. Aronow and James M. Robins and Theo Saarinen and Fredrik Savje and Jasjeet S. Sekhon},
  year={2021}
}
We argue that randomized controlled trials (RCTs) are special even among settings where average treatment effects are identified by a nonparametric unconfoundedness assumption. This claim follows from two results of Robins and Ritov (1997): (1) with at least one continuous covariate control, no estimator of the average treatment effect exists which is uniformly consistent without further assumptions, (2) knowledge of the propensity score yields a consistent estimator and confidence intervals at… 

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