Chapter 21: typos

[maswiebe]

In Ch. 21, every instance of 'input' should be 'impute'.

(1)

For the second stage, we input the treatment effect for the control and for the treated using the models above

should be

For the second stage, we impute the treatment effect for the control and for the treated using the models above

(2)

The treatment effect it inputs is non linear, since it doesn’t capture the non-linearity in the Y variable.

should be

The treatment effect it imputes is non linear, since it doesn’t capture the non-linearity in the Y variable.

(3)

So we have one model that is wrong because we’ve input the treatment effects wrongly

should be

So we have one model that is wrong because we’ve imputed the treatment effects wrongly