title: Comment: improved local efficiency and double robustness.
abstract: For missing data and causal inference problems, Rubin and van der Laan (2008) proposed estimators to achieve so-called improved local efficiency. We show that their estimators agree with existing estimators in the case of linear models, point out that one particular version of their estimators is also doubly robust, and suggest an extension for where the propensity score is estimated.
authors.affiliation: Rutgers University.
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Tan
mesh_terms: D003198:Computer Simulation; D006801:Humans; D016014:Linear Models; D015233:Models, Statistical; D057216:Propensity Score