This article reviews and generalizes the sufficient statistics approach to policy evaluation. The idea of is that welfare effect changes can be expressed in terms estimable reduced-form elasticities, allowing for evaluation without estimating structural primitives fully specified models. relies on three assumptions: are small, government only source market imperfection, a set high-level restric...

The requirement of constant censoring parameter β in Koziol–Green (KG) model is too restrictive. When covariates are present, the conditional KG model (Veraverbekea and Cadarso-Suárez, 2000) which allows β to be dependent on the covariates is more realistic. In this paper, using sufficient dimension reduction methods, we provide a model-free diagnostic tool to test if β is a function of the cov...