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VIOLATING IGNORABILITY OF TREATMENT BY CONTROLLING FOR TOO MANY FACTORS

Published online by Cambridge University Press:  22 August 2005

Jeffrey M. Wooldridge
Affiliation:
Michigan State University

Abstract

This problem shows how the key ignorability-of-treatment assumption used in estimating treatment effects can be violated when certain factors are included among the covariates. The case considered is when there are J + 1 treatment levels, treatment is randomized with respect to potential outcomes, but the distribution of included covariates differs across treatment levels.

Type
NOTES AND PROBLEMS
Copyright
© 2005 Cambridge University Press

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References

REFERENCES

Heckman, J.J., H. Ichimura, & P. Todd (1997) Matching as an econometric evaluation estimator. Review of Economic Studies 65, 261294.Google Scholar
Rosenbaum, P.R. & D.B. Rubin (1983) The central role of the propensity score in observational studies for causal effects. Biometrika 70, 4155.Google Scholar
Wooldridge, J.M. (2002) Econometric Analysis of Cross Section and Panel Data. MIT Press.