Slide 40
Slide 40 text
A More Advanced Model: Causal Trees
Athey and Imbens, arxiv:1504.01132v3
leaf a
leaf b
leaf c leaf d
1
N
ˆ
τ2
i
∑
ˆ
τ ≡ ˆ
µ(T, x)− ˆ
µ(C, x)
income > $50k
gender
male
female
age < 50
treatment
control
§ A CART-like or random forest-like
algorithm but with an altered split
criterion for estimating heterogeneous
treatment effects
§ Choose the split variables and split
points from the observable covariates to
maximize
where
ˆ
µ(T, x) =
1
N
leaf
Y
i
i∈leaf ,T
∑
ˆ
µ(C, x) =
1
N
leaf
Y
i
i∈leaf ,C
∑