Abstract
Research has shown that foreign direct investment (FDI) encourages economic growth at the state level. We also know that knowledge spillovers, measured via patent counts, contribute to economic growth. Using an instrumental variable approach, this paper demonstrates that FDI increases patent rates in US states, thereby providing a link for the mechanism through which FDI impacts growth. Moreover, we find that FDI in neighboring states has just as strong an impact on patent rates, giving further credence to the notion that knowledge can spill across state borders.