title: Optimal restricted estimation for more efficient longitudinal causal inference.
abstract: Efficient semiparametric estimation of longitudinal causal effects is often analytically or computationally intractable. We propose a novel restricted estimation approach for increasing efficiency, which can be used with other techniques, is straightforward to implement, and requires no additional modeling assumptions.
authors.affiliation: Department of Biostatistics and Epidemiology, University of Pennsylvania.
authors.forename: Edward H
authors.initials: EH
authors.lastname: Kennedy
authors.affiliation: Department of Biostatistics and Epidemiology, University of Pennsylvania.
authors.forename: Marshall M
authors.initials: MM
authors.lastname: Joffe
authors.affiliation: Department of Statistics, The Wharton School, University of Pennsylvania.
authors.forename: Dylan S
authors.initials: DS
authors.lastname: Small
keywords: Doubly robust; Generalized method of moments; Marginal structural model; Semiparametric efficiency; Structural nested model; Time-varying confounding