WhatIf: R software for evaluating counterfactuals

Abstract

WhatIf is an R package that implements the methods for evaluating counterfactuals introduced in King and Zong (2006a) and King and Zong (2006b). It offers easy-to-use techniques for assessing a counterfactual's model dependence without having to conduct sensitivity testing over specified classes of models. These same methods can be used to approximate the common support of the treatment and control groups in causal inference.