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How much should we trust differences-in-differences estimates?
Bertrand, Marianne, (2001)
Consistent, positive definite covariance matrix estimation of Heckman's two-step estimators
Ryu, Keunkwan, (1996)
Bertrand, Marianne, (2002)
How Much Should We Trust Differences-in-Differences Estimates?
Bertrand, Marianne, (2021)