We derive general, yet simple, sharp bounds on the size of the omitted variable bias for a broad class of causal parameters that can be identified as linear functionals of the conditional expectation function of the outcome. Such functionals encompass many of the traditional targets of...

We derive general, yet simple, sharp bounds on the size of the omitted variable bias for a broad class of causal parameters that can be identified as linear functionals of the conditional expectation function of the outcome. Such functionals encompass many of the traditional targets of...

Bias correction can often improve the finite sample performance of estimators. We show that the choice of bias correction method has no effect on the higherorder variance of semiparametrically efficient parametric estimators, so long as the estimate of the bias is asymptotically linear. It is...