The Triple Difference Estimator

By A. Olden, Jarle Møen. Social Science Research Network, 2020

302 citations recorded by the source corpus.

Triple difference has become a widely used estimator in empirical work. A close reading of articles in top economics journals reveals that the use of the estimator to a large extent rests on intuition. The identifying assumptions are neither formally derived nor generally agreed on. We give a complete presentation of the triple difference estimator, and show that even though the estimator can be computed as the difference between two difference-in-differences estimators, it does not require two parallel trend assumptions to have a causal interpretation. The reason is that the difference between two biased difference-in-differences estimators will be unbiased as long as the bias is the same in both estimators. This requires only one parallel trend assumption to hold.

Subfields: Statistics and Probability

View Paper: https://www.semanticscholar.org/paper/a38da99560094813b2b7be7509f899c49b214e30