We give two new approaches to testing a conditional form of exogeneity. This conditionensures unconfoundedness and identication of eects of interest in structural systems. Asthese approaches do not rely on the absence of causal eects of treatment under the null,they complement earlier methods of...

We give two new approaches to testing a conditional form of exogeneity. This condition ensures unconfoundedness and identification of effects of interest in structural systems. As these approaches do not rely on the absence of causal effects of treatment under the null, they complement earlier...

This paper demonstrates the extensive scope of an alternative to standard instrumental variables methods, namely covariate-based methods, for identifying and estimating effects of interest in general structural systems. As we show, commonly used econometric methods, specifically parametric,...

The method of indirect least squares (ILS) using a proxy for a discrete instrument is shown to identify a weighted average of local treatment effects. The weights are nonnegative if and only if the proxy is intensity preserving for the instrument. A similar result holds for instrumental...

Do individuals use all information at their disposal when forming expectations about future events? In this paper we present an econometric framework to answer this question. We show how individual information sets can be characterized by simple nonparametric exclusion restrictions and provide a...

We study the scope of local indirect least squares (LILS) methods for nonparametrically estimating average marginal effects of an endogenous cause X on a response Y in triangular structural systems that need not exhibit linearity, separability, or monotonicity in scalar unobservables. One main...