A Note on Endogenous Control Variables in Evaluation Studies
The paper addresses the issue of potentially endogenous control variables in evaluation studies based on the assumption that selection bias can be avoided by conditioning on observed variables. It shows that the standard formulation of the conditional independence (CIA) or selection on observables assumption obscures the endogeneity problem. The paper clarifies the issue by suggesting a CIA based on exogenous (potential) outcomes as well as explicit exogeneity conditions. The refined CIA allows to asses the endogeneity bias as well as the plausibility of the CIA, because it allows a separate discussion of (i) the problems of missing variables that are necessary to avoid selection bias, and (ii) the problem that some of the control variables may be influenced by the treatment.
|Date of creation:||Aug 2005|
|Date of revision:|
|Contact details of provider:|| Postal: Dufourstrasse 50, CH - 9000 St.Gallen|
Phone: +41 71 224 23 25
Fax: +41 71 224 31 35
Web page: http://www.seps.unisg.ch/
More information through EDIRC
Please report citation or reference errors to , or , if you are the registered author of the cited work, log in to your RePEc Author Service profile, click on "citations" and make appropriate adjustments.:
- Michael Lechner, 2002. "Program Heterogeneity And Propensity Score Matching: An Application To The Evaluation Of Active Labor Market Policies," The Review of Economics and Statistics, MIT Press, vol. 84(2), pages 205-220, May.
- Barbara Sianesi, 2004. "An Evaluation of the Swedish System of Active Labor Market Programs in the 1990s," The Review of Economics and Statistics, MIT Press, vol. 86(1), pages 133-155, February.
- Michael Gerfin & Michael Lechner, 2002.
"A Microeconometric Evaluation of the Active Labour Market Policy in Switzerland,"
Royal Economic Society, vol. 112(482), pages 854-893, October.
- Gerfin, Michael & Lechner, Michael, 2000. "Microeconometric Evaluation of the Active Labour Market Policy in Switzerland," IZA Discussion Papers 154, Institute for the Study of Labor (IZA).
- Guido W. Imbens, 2003.
"Nonparametric Estimation of Average Treatment Effects under Exogeneity: A Review,"
NBER Technical Working Papers
0294, National Bureau of Economic Research, Inc.
- Guido W. Imbens, 2004. "Nonparametric Estimation of Average Treatment Effects Under Exogeneity: A Review," The Review of Economics and Statistics, MIT Press, vol. 86(1), pages 4-29, February.
- Donald B. Rubin, 2004. "Direct and Indirect Causal Effects via Potential Outcomes," Scandinavian Journal of Statistics, Danish Society for Theoretical Statistics;Finnish Statistical Society;Norwegian Statistical Association;Swedish Statistical Association, vol. 31(2), pages 161-170.
- Donald B. Rubin, 2005. "Causal Inference Using Potential Outcomes: Design, Modeling, Decisions," Journal of the American Statistical Association, American Statistical Association, vol. 100, pages 322-331, March.
When requesting a correction, please mention this item's handle: RePEc:usg:dp2005:2005-16. See general information about how to correct material in RePEc.
For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: (Joerg Baumberger)
If references are entirely missing, you can add them using this form.