First Course Ding: Instrumental Variables (Chapters 21 And 23)

This section groups the IV chapters implemented in the current batch:

• Chapter 21: An Experimental Perspective on the Instrumental Variable
• Chapter 23: An Econometric Perspective on the Instrumental Variable

The split mirrors the book:

• Chapter 21 is about randomized assignment, compliance, and the Wald estimand
• Chapter 23 is about linear IV as an econometric estimator, with overidentification and moment conditions

1 What Is Covered

• Wald ratios with delta-method and bootstrap uncertainty
• covariate-adjusted TwoSLS
• explicit IV moments written as a first-class GMM problem
• a Card-style schooling example with multiple excluded instruments