198 Measurement Error 5 Measurement error in X (intuition)

Discover why measurement error in the independent variable (X) is a critical concern in econometrics. Unlike errors in the dependent variable (Y), noise in X systematically biases OLS estimates. This video visually explains how OLS, treating the noisy X as truth, misinterprets true variation, diluting the signal and weakening the observed relationship. Learn how this leads to an estimated regression line that is flatter than reality, systematically pulling the slope towards zero—a phenomenon known as attenuation bias. This persistent bias cannot be resolved by simply increasing sample size. Visit AxiomTutoring.com for more resources and subscribe to @AxiomTutoringCourses for expert econometrics insights.