“Unobservable Selection and Coefficient Stability: Theory and Evidence” (2016), by Emily F. Oster. Mathematics research paper. Original abstract below, unchanged. No free PDF was found.

Unobservable Selection and Coefficient Stability: Theory and Evidence

Emily F. Oster · September 10, 2016 · Mathematics

Abstract

A common approach to evaluating robustness to omitted variable bias is to observe coefficient movements after inclusion of controls. This is informative only if selection on observables is informative about selection on unobservables. Although this link is known in theory in existing literature, very few empirical articles approach this formally. I develop an extension of the theory that connects bias explicitly to coefficient stability. I show that it is necessary to take into account coefficient and R-squared movements. I develop a formal bounding argument. I show two validation exercises and discuss application to the economics literature. Supplementary materials for this article are available online.

Source page DOI: 10.1080/07350015.2016.1227711