Causal Inference, Instrumental Variables, Stats 361, Stanford, Data Science.
level (e.g. academic history) and employees ability (e.g. IQ, certificates, any domain-specific skills, etc) as: ln(wage) = a + b・educ + c・ability + u However, since it was actually quite difficult to quantify the ability, he omitted the term. ln(wage) = a + b・educ + v This operation in turn caused