White, Halbert, and Karim Chalak. “Testing a Conditional Form of Exogeneity”. Boston College Working Papers in Economics 733, 2010.
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 methods of Rosenbaum (1987) and Heckman and Hotz (1989).