188 IV11b 2SLS worked example reversed (scaling)

This video delves into why Ordinary Least Squares (OLS) often fails to provide causal estimates when endogeneity is present. It explains that OLS utilizes all variation in education, including contaminated variation from factors like ability, motivation, and reverse causality. In contrast, Instrumental Variables (IV) estimation strategically isolates clean variation in education, such as that caused by distance from university. The video clarifies that the instrument creates this clean variation, which Two-Stage Least Squares (2SLS) then uses to estimate the true causal effect. Through proportional reasoning, it demonstrates how IV scales the instrument's effect on earnings by its effect on education, ensuring a causally interpretable result. Learn more about econometrics at AxiomTutoring.com and subscribe to @AxiomTutoringCourses for more insights.