- Published Online:
- 2018-06-13
- Citation Information:
- Journal of Econometric Methods, Volume 8, Issue 1, 20170016, eISSN 2156-6674, DOI: https://doi.org/10.1515/jem-2017-0016.
Using a sequential conditional independence assumption, this paper discusses fully nonparametric estimation of natural direct and indirect causal effects in causal mediation analysis based on inverse probability weighting. We propose estimators of the average indirect effect of a binary treatment, which operates through intermediate variables (or mediators) on the causal path between the treatment and the outcome, as well as the unmediated direct effect. In a first step, treatment propensity scores given the mediator and observed covariates or given covariates alone are estimated by nonparametric series logit estimation. In a second step, they are used to reweigh observations in order to estimate the effects of interest. We establish root-n consistency and asymptotic normality of this approach as well as a weighted version thereof. The latter allows evaluating effects on specific subgroups like the treated, for which we derive the asymptotic properties under estimated propensity scores. We also provide a simulation study and an application to an information intervention about male circumcisions.
Abrevaya, J., Y.-C. Hsu, and R. P. Lieli. 2015. “Estimating Conditional Average Treatment Effects.” Journal of Business & Economic Statistics 33 (4): 485–505.
Albert, J. M. 2008. “Mediation analysis via potential outcomes models.” Statistics in Medicine 27: 1282–1304.
Albert, J. M., and S. Nelson. 2011. “Generalized causal mediation analysis.” Biometrics 67: 1028–1038.
An, W., and X. Wang. 2016. “Instrumental Variable Estimation of Causal Effects through Local Average Response Functions.” Journal of Statistical Software 71: 1–13.
Baron, R. M., and D. A. Kenny. 1986. “The Moderator-Mediator Variable Distinction in Social Psychological Research: Conceptual, Strategic, and Statistical Considerations.” Journal of Personality and Social Psychology 51: 1173–1182.
Busso, M., J. DiNardo, and J .McCrary. 2014. “New Evidence on the Finite Sample Properties of Propensity Score Matching and Reweighting Estimators.” Review of Economics and Statistics 96 (5): 885–897.
Chinkhumba, J., S. Godlonton, and R. Thornton. 2014. “The Demand for Medical Male Circumcision.” American Economic Journal: Applied Economics 6: 152–177.
Donald, S. G., and Y.-C. Hsu. 2014. “Estimation and Inference for Distribution Functions and Quantile Functions in Treatment Effect Models.” Journal of Econometrics 178: 383–397.
Donald, S. G., Y.-C. Hsu, and R. P. Lieli. 2014. “Testing the Unconfoundedness Assumption via Inverse Probability Weighted Estimators of (L)ATT.” Journal of Business & Economic Statistics 32 (3): 395–415.
Donald, S. G., Y.-C. Hsu, and R. P. Lieli. 2014. “Inverse Probability Weighted Estimation of Local Average Treatment Effects: A Higher Order MSE Expansion.” Statistics and Probability Letters 95:132–138.
Flores, C. A., and A. Flores-Lagunes. 2009. “Identification and Estimation of Causal Mechanisms and Net Effects of a Treatment under Unconfoundedness.” IZA Dicussion Paper No. 4237.
Gelman, A., and G. Imbens. 2013. “Why ask Why? Forward Causal Inference and Reverse Causal Questions.” NBER Working Paper No. 19614.
Hayes, A. F. 2017. An introduction to mediation, moderation, and conditional process analysis: A regression-based approach. New york, USA: Guilford Press.
Hirano, K., G. W. Imbens, and G. Ridder. 2003. “Efficient Estimation of Average Treatment Effects Using the Estimated Propensity Score.” Econometrica 71: 1161–1189.
Hong, G. 2010. “Ratio of mediator probability weighting for estimating natural direct and indirect effects,” in JSM Proceedings, Biometrics Section, pp. 2401–2415. Alexandria, VA: American Statistical Association.
Hong, G. 2015. Causality in a social world: Moderation, mediation and spill-over. West Sussex, UK: John Wiley & Sons, Ltd.
Hsu, Y.-C. 2017. “Consistent Tests for Conditional Treatment Effects.” Econometrics Journal 20 (1):1–22.
Huber, M. 2014. “Identifying causal mechanisms (primarily) based on inverse probability weighting.” Journal of Applied Econometrics 29: 920–943.
Ichimura, H., and O. Linton. 2005. “Asymptotic Expansions for Some Semiparametric Program Evaluation Estimators,” in Identification and Inference for Econometric Models: essays in honor of Thomas Rothenberg, edited by D. Andrews and J. Stock. Cambridge, England: Cambridge University Press.
Imai, K., L. Keele, and T. Yamamoto. 2010. “Identification, Inference and Sensitivity Analysis for Causal Mediation Effects.” Statistical Science 25: 51–71.
Imai, K., and T. Yamamoto. 2013. “Identification and Sensitivity Analysis for Multiple Causal Mechanisms: Revisiting Evidence from Framing Experiments.” Political Analysis 21: 141–171.
Imbens, G. W. 2004. “Nonparametric Estimation of Average Treatment Effects under Exogeneity: A Review.” The Review of Economics and Statistics 86: 4–29.
Imbens, G. W., and J. M. Wooldridge. 2009. “Recent Developments in the Econometrics of Program Evaluation.” Journal of Economic Literature 47: 5–86.
Judd, C. M., and D. A. Kenny. 1981. “Process Analysis: Estimating Mediation in Treatment Evaluations.” Evaluation Review 5: 602–619.
Li, Q., and J. S. Racine. 2007. Nanparametric econometrics: theory and practice. Princeton, New Jersey: Princeton Universiry Press.
MacKinnon, D. P. 2008. Introduction to Statistical Mediation Analysis. New York: Taylor and Francis.
Pearl, J. 2001. “Direct and indirect effects,” in Proceedings of the Seventeenth Conference on Uncertainty in Artificial Intelligence, pp. 411–420, San Francisco. Morgan Kaufman.
Petersen, M. L., S. E. Sinisi, and M. J. van der Laan. 2006. “Estimation of Direct Causal Effects.” Epidemiology 17: 276–284.
Robins, J. M. 2003. “Semantics of causal DAG models and the identification of direct and indirect effects,” in In Highly Structured Stochastic Systems, edited by P. Green, N. Hjort, and S. Richardson, pp. 70–81, Oxford: Oxford University Press.
Robins, J. M., and S. Greenland. 1992. “Identifiability and Exchangeability for Direct and Indirect Effects.” Epidemiology 3: 143–155.
Rubin, D. B. 1974. “Estimating Causal Effects of Treatments in Randomized and Nonrandomized Studies.” Journal of Educational Psychology 66: 688–701.
Rubin, D. B. 2004. “Direct and Indirect Causal Effects via Potential Outcomes.” Scandinavian Journal of Statistics 31: 161–170.
Tchetgen Tchetgen, E. J. 2013. “Inverse Odds Ratio-Weighted Estimation for Causal Mediation Analysis.” Statistics in Medicine 32: 4567–4580.
Tchetgen Tchetgen, E. J., and I. Shpitser. 2012. “Semiparametric theory for causal mediation analysis: Efficiency bounds, multiple robustness, and sensitivity analysis.” The Annals of Statistics 40: 1816–1845.
Ten Have, T. R., M. M. Joffe, K. G. Lynch, G. K. Brown, S. A. Maisto, and A. T. Beck. 2007. “Causal mediation analyses with rank preserving models.” Biometrics 63: 926–934.
Tingley, D., T. Yamamoto, K. Hirose, K. Imai, and L. Keele. 2014. “Mediation: R package for causal mediation analysis.” Journal of Statistical Software 59: 1–38.
VanderWeele, T. J. 2009. “Marginal Structural Models for the Estimation of Direct and Indirect Effects.” Epidemiology 20: 18–26.
Vansteelandt, S., M. Bekaert, and T. Lange. 2012. “Imputation Strategies for the Estimation of Natural Direct and Indirect Effects.” Epidemiologic Methods 1: 129–158.