The DRDID package implements different estimators for the average treatment effect on the treated in difference-in-differences (DID) setups where the parallel trends assumption holds after you condition on a vector of pre-treatment covariates. The main estimators implemented here are the locally efficient, doubly-robust DID estimators proposed by Sant'Anna and Zhao (2020) <https://arxiv.org/abs/1812.01723>. A number of other DID estimators discussed in Sant'Anna and Zhao (2020) are also implemented.

## References

Sant'Anna, Pedro H. C. and Zhao, Jun. (2020), "Doubly Robust Difference-in-Differences Estimators." Journal of Econometrics, Vol. 219 (1), pp. 101-122, doi: 10.1016/j.jeconom.2020.06.003