This paper uses a gravity framework to investigate the effects of distance as well as subnational and national borders in knowledge spillovers. Drawing on the NBER Patent Citations Database, we examine patent citations data at metropolitan level within the U.S. and the 38 largest patent-cited...

Why do borders still matter for economic activity? The reunification of Germany in 1990 provides a unique natural experiment for examining the effect of political borders on trade both in the cross-section and over time. With the fall of the Berlin Wall and the rapid formation of a political and...

Many studies have found that international borders represent large barriers to trade. But how do international borders compare to domestic border barriers? We investigate international and domestic border barriers in a unified framework. We consider a unique data set of exports from individual...

This paper reviews the economics approach to conflict and national borders. The paper (a) provides a summary of ideas and concepts from the economics literature on the size of nations; (b) illustrates them within a simple analytical framework where populations fight over borders and resources,...

This analysis employs cointegration methods and semiparametric regression in order to assess the integration of maize markets and the factors determining national and cross-national transmission of price signals in Sub-Saharan Africa. We use a rich dataset of 16 series of wholesale maize prices...

This paper presents concepts from economic analysis that shed light on the formation and breakup of sovereign states. First, we discuss the key trade-off between economies of scale in the provision of public goods and political costs from heterogeneity of preferences. Second, we present four...