Abstract Marginal Structural Models (MSMs), with the associated method of inverse probability weighting (IPW), have become increasingly popular in epidemiology to model and estimate the joint effects of a sequence of exposures. This popularity is largely related to the relative simplicity of the...

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...