Arbeitspapier

Effects of correlated covariates on the efficiency of matching and inverse probability weighting estimators for causal inference

In observational studies the overall aim when fitting a model for the propensity score is to reduce bias for an estimator of the causal effect. For this purpose guidelines for covariate selection for propensity score models have been proposed in the causal inference literature. To make the assumption of an unconfounded treatment plausible researchers might be tempted to include many, possibly correlated, covariates in the propensity score model. In this paper we study how the efficiency of matching and inverse probability weighting estimators for average causal effects change when the covariates are correlated. We investigate the case with multivariate normal covariates and linear models for the propensity score and potential outcomes and show results under different model assumptions. We show that the correlation can both increase and decrease the large sample variances of the estimators, and that the corrrelation affects the efficiency of the estimators differently, both with regard to direction and magnitude. Moreover, the strength of the confounding towards the outcome and the treatment plays an important role.

Sprache
Englisch

Erschienen in
Series: Working Paper ; No. 2013:5

Klassifikation
Wirtschaft
Estimation: General
Econometric and Statistical Methods: Special Topics: General
Model Evaluation, Validation, and Selection
Thema
efficiency bound
observational study
propensity score
variable selection
Schätztheorie
Modellierung

Ereignis
Geistige Schöpfung
(wer)
Pingel, Ronnie
Waernbaum, Ingeborg
Ereignis
Veröffentlichung
(wer)
Institute for Evaluation of Labour Market and Education Policy (IFAU)
(wo)
Uppsala
(wann)
2013

Handle
Letzte Aktualisierung
10.03.2025, 11:43 MEZ

Datenpartner

Dieses Objekt wird bereitgestellt von:
ZBW - Deutsche Zentralbibliothek für Wirtschaftswissenschaften - Leibniz-Informationszentrum Wirtschaft. Bei Fragen zum Objekt wenden Sie sich bitte an den Datenpartner.

Objekttyp

  • Arbeitspapier

Beteiligte

  • Pingel, Ronnie
  • Waernbaum, Ingeborg
  • Institute for Evaluation of Labour Market and Education Policy (IFAU)

Entstanden

  • 2013

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