Purpose: While the popularity of online shopping has increased in recent years, surprisingly little research has examined the factors affecting consumers’ behavior in this context. Furthermore, though a widespread problem for companies, the phenomenon of online shopping cart abandonment has...

Abstract Many of the secondary outcomes in observational studies and randomized trials are rare. Methods for estimating causal effects and associations with rare outcomes, however, are limited, and this represents a missed opportunity for investigation. In this article, we construct a new...

Abstract This paper describes a targeted maximum likelihood estimator (TMLE) for the parameters of longitudinal static and dynamic marginal structural models. We consider a longitudinal data structure consisting of baseline covariates, time-dependent intervention nodes, intermediate...

Abstract The stratum-specific treatment effect function is a random variable giving the average treatment effect (ATE) for a randomly drawn stratum of potential confounders a clinician may use to assign treatment. In addition to the ATE, the variance of the stratum-specific treatment effect...

The FDA employs an average-patient standard when reviewing drugs: it approves a drug only if is safe and effective for the average patient in a clinical trial. It is common, however, for patients to respond differently to a drug. Therefore, the average-patient standard can reject a drug that...

The FDA employs an average-patient standard when reviewing drugs: it approves a drug only if the average patient (in clinical trials) does better on the drug than on control. It is common, however, for different patients to respond differently to a drug. Therefore, the average-patient standard...