Public health regulation and mortality: Evidence from early 20th century milk laws.

In this paper, I estimate the impact of city-level public health regulations in the market for cow's milk on the mortality of infants and young children between 1900 and 1920. I find that the introduction of city-level dairy farm inspections reduced mortality from Diarrhea & Enteritis for one-year-old children by 1.3 annual deaths per thousand, a 14 percent effect relative to the baseline rate for this cause and a 3 percent effect relative to the baseline rate for all causes for this age group. Back-of-the-envelope calculations reveal that the benefits from these regulations exceeded costs by at least a factor of two.