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Synthetic Difference In Differences

Author

Listed:
  • Dmitry Arkhangelsky
  • Susan Athey
  • David A. Hirshberg
  • Guido W. Imbens
  • Stefan Wager

Abstract

We present a new estimator for causal effects with panel data that builds on insights behind the widely used difference in differences and synthetic control methods. Relative to these methods we find, both theoretically and empirically, that this "synthetic difference in differences" estimator has desirable robustness properties, and that it performs well in settings where the conventional estimators are commonly used in practice. We study the asymptotic behavior of the estimator when the systematic part of the outcome model includes latent unit factors interacted with latent time factors, and we present conditions for consistency and asymptotic normality.

Suggested Citation

  • Dmitry Arkhangelsky & Susan Athey & David A. Hirshberg & Guido W. Imbens & Stefan Wager, 2019. "Synthetic Difference In Differences," NBER Working Papers 25532, National Bureau of Economic Research, Inc.
    • Handle: RePEc:nbr:nberwo:25532
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    References listed on IDEAS

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    • C01 - Mathematical and Quantitative Methods - - General - - - Econometrics

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