Do urban agglomeration effects and household amenities have a skill bias?

There are several hypotheses why urban scale affects wages. Most focus on agglomeration economies that increase labor demand, especially for high-skilled workers (e.g., dynamic externalities stress knowledge transfers, and imply the urban wage gap favors skilled workers). Others stress urban amenities that increase labor supply and decrease wages. Amenities should have a stronger influence on affluent households if they are normal goods. By examining whether urban-scale affects net returns to education, it can be determined whether skilled workers are influenced more by urban productivity or amenities. Empirical results suggest net returns to education decline with urban scale, implying a key role for urban amenities in affecting skilled workers.