Estimation of Treatment Effects Without an Exclusion Restriction: with an Application to the Analysis of the School Breakfast Program
---- Acknowledgements -----
The authors are grateful for comments from Jay Bhattacharya, Chris Bollinger, Ozkan Eren, Juan Carlos Escanciano, James Heckman, Keisuke Hirano, Michael Lechner, Arthur Lewbel, Salvador Navarro-Lozano, Denis Nekipelov, Jeff Smith, Aaron Yelowitz, seminar participants at SMU and U Kentucky, and conference participants at the 2009 Econometric Society Winter Meetings and the Fifth IZA Conference on Labor Market Policy Evaluation. Mehtabul Azam provided valuable research assistance. A previous version of this paper was circulated under the title "Minimizing Bias in Selection on Observables
Estimators When Unconfoundness Fails.'' Stata code to implement the estimators used is available from the authors. The views expressed herein are those of the author(s) and do not necessarily reflect the views of the National Bureau of Economic Research.