Legislating Longevity: State Public Health Laws and Mortality in the Early Twentieth Century

State legislatures enacted numerous public-health laws during the twentieth century, most of which likely had negligible effects on mortality. Using data on the universe of state-level public-health laws and regulations, I test whether these laws, taken together, account for a meaningful decline in mortality. To address endogeneity, I instrument for public-health legislation using the legislative calendar. Both OLS and IV estimates indicate that public-health laws reduced mortality, whereas other laws and repeals of public-health laws did not. Legislatures were most effective at reducing deaths from waterborne and drainage-related diseases, half as effective for airborne communicable diseases, and one-fifth as effective for noncommunicable diseases. I use text analysis to classify the laws into twenty topics and find that laws targeting particular causes of death produced larger mortality declines for those causes. The universe of public-health laws can account for approximately two-thirds of the mortality decline during the study period.