We introduce two simple new variants of the Jackknife Instrumental Variables (JIVE) estimator for overidentified linear models and show that they are superior to the existing JIVE estimator, significantly improving on its small sample bias properties. We also compare our new estimators to...

Many interesting and important economic questions relate to the e§ects of binary treatments such as starting a college degree or participating in a job training program. The causal e§ects of these treatments are likely to be heterogeneous and recent research has emphasized the estimation of...