Mechanistic Interpretability as Statistical Estimation: A Variance Analysis
Researchers demonstrate that mechanistic interpretability—the process of reverse-engineering AI model behaviors through circuit discovery—suffers from fundamental statistical instability due to high variance in causal mediation analysis. The findings reveal that circuit structures are fragile and highly sensitive to input data and hyperparameter changes, calling into question the scientific validity of existing MI methodologies and necessitating stricter statistical practices in the field.