Spreading the word: geography, policy and knowledge spillovers

Using new data on citations to university patents and scientific publications, we study how geography affects university knowledge spillovers. Citations to patents decline sharply with distance up to about 150 miles and are strongly constrained by state borders. Distance also constrains citations to scientific publications, but the impact is less sharp and persists over greater distances. The state border effect for publications is significant only for lower quality public universities. We show that the state border effect is heterogeneous, and is strongly influenced by university and state characteristics and policies. It is larger for public universities and those with strong local development policies. The border effect is larger in states with strong non-compete laws that facilitate intrastate labor mobility, states with greater reliance on in-state educated scientists and engineers, and states with lower rates of interstate scientific labor mobility. We also confirm the impact of non-compete statutes by studying a policy reform in Michigan.