Assessing bias in the estimation of causal effects: Rosenbaum bounds on matching estimators and instrumental variables estimation with imperfect instruments
Propensity score matching provides an estimate of the effect of a 'treatment' variable on an outcome variable that is largely free of bias arising from an association between treatment status and observable variables. However, matching methods are not robust against 'hidden bias' arising from unobserved variables that simultaneously affect assignment to treatment and the outcome variable. One strategy for addressing this problem is the Rosenbaum bounds approach, which allows the analyst to determine how strongly an unmeasured confounding variable must affect selection into treatment in order to undermine the conclusions about causal effects from a matching analysis. Instrumental variables (IV) estimation provides an alternative strategy for the estimation of causal effects, but the method typically reduces the precision of the estimate and has an additional source of uncertainty that derives from the untestable nature of the assumptions of the IV approach. A method of assessing this additional uncertainty is proposed so that the total uncertainty of the IV approach can be compared with the Rosenbaum bounds approach to uncertainty using matching methods. Because the approaches rely on different information and different assumptions, they provide complementary information about causal relationships. The approach is illustrated via an analysis of the impact of unemployment insurance on the timing of reemployment, the postunemployment wage, and the probability of relocation, using data from several panels of the Survey of Income and Program Participation (SIPP).
|Date of creation:||2004|
|Contact details of provider:|| Postal: Reichpietschufer 50, 10785 Berlin, Germany|
Phone: ++49 - 30 - 25491 - 0
Fax: ++49 - 30 - 25491 - 684
Web page: http://www.wzb.eu/
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.:
- Joshua D. Angrist & Guido W. Imbens, 1995.
"Identification and Estimation of Local Average Treatment Effects,"
NBER Technical Working Papers
0118, National Bureau of Economic Research, Inc.
- Imbens, Guido W & Angrist, Joshua D, 1994. "Identification and Estimation of Local Average Treatment Effects," Econometrica, Econometric Society, vol. 62(2), pages 467-475, March.
- Michael E. Sobel, 1996. "An Introduction to Causal Inference," Sociological Methods & Research, SAGE Publishing, vol. 24(3), pages 353-379, February.
- Robert A. Moffitt, 1996. "Selection Bias Adjustment in Treatment-Effect Models as a Method of Aggregation," NBER Technical Working Papers 0187, National Bureau of Economic Research, Inc.
- James Heckman, 1997. "Instrumental Variables: A Study of Implicit Behavioral Assumptions Used in Making Program Evaluations," Journal of Human Resources, University of Wisconsin Press, vol. 32(3), pages 441-462.
When requesting a correction, please mention this item's handle: RePEc:zbw:wzblpe:spi2004101. 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: (ZBW - German National Library of Economics)
If references are entirely missing, you can add them using this form.