Skills Beget Skills: Evidence from Historical School Reforms Targeting Health and Further Education

Abstract: This paper investigates the dynamic complementarity between school health and education reforms implemented in Denmark between 1940 and 1965: the introduction of school doctors and the expansion of secondary education. Using a staggered difference-in-differences approach for multiple treatments, we study the reform effects on individuals' outcomes in the ages 55-64. We find that each reform leads to significant improvements in health and education outcomes, including reduced mortality, fewer hospitalizations, and higher educational attainment. The singular impact of each reform is doubled when both reforms are implemented together, resulting in a 9 percent increase in earnings. These findings underscore high societal returns to complementary school investments in the long term.