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Augmented inverse probability weighting

As explained in Causal Inference for Data Science

Augmented inverse probability weighting is a doubly robust causal estimation method that combines an outcome model with inverse-probability treatment weighting.

When estimating whether a treatment changes an outcome, augmented inverse probability weighting (AIPW) combines an outcome model with inverse-probability treatment weighting. Its doubly robust design remains unbiased when either component is correctly specified. section 8.3

AIPW brings together two estimates built from the same confounder information:

  • A T-learner estimates the expected outcome under treatment and control, using functions that approximate E[Y|C,T=1] and E[Y|C,T=0]. section 8.3
  • IPW estimates each subject’s treatment probability, or propensity score, and uses those probabilities for weighting. section 8.3
  • The AIPW estimator augments the weighting estimate with outcome-model predictions, providing protection if one model is unbiased. section 8.3

The setup assumes a binary treatment, an observed outcome, measured confounders, and no unobserved confounders. AIPW is recommended for binary-treatment problems because it is root-n consistent, efficient, and supports uncertainty estimates through confidence intervals. section 8.3 section 8.6

Table 8.4 Available data with propensity scores calculated
Y
T
C 1
…
Cp
y 1
t 1
c 1 1
…
c 1 p
…
…
…
…
…
y n
t n
c n 1
…
c n p

Use the treatment, outcome, and confounder columns as the data structure required before calculating propensity scores and applying AIPW. section 8.3

Estimating treatment effects with DoubleML

In the right-heart catheterization dataset, estimate the average treatment effect of swang1 on death and calculate its confidence interval with DoubleML. The package exposes AIPW through its interactive regression model (IRM), with hyperparameter tuning performed on cross-fitting folds. section 8.3.1

How Causal Inference for Data Science covers it

How deep it goes
Explains the two component estimators, their combination, assumptions, and practical implementation without developing broader doubly robust theory.
Examples
Uses a treatment-outcome-confounder table and a right-heart catheterization dataset involving swang1 and death.
What it assumes
Assumes binary treatment, measured confounders, the adjustment formula, and no unobserved confounding.
What you can do after
Apply AIPW through DoubleML’s interactive regression model and report an average treatment effect with a confidence interval.
How it connects
Connects T-learners, inverse probability weighting, propensity scores, double machine learning, cross-fitting, and confidence intervals.

Related concepts

This explainer was generated by Manning's knowledge graph from the text of Causal Inference for Data Science. The section links point to the parts of the book it draws on.