The United States and European Union differ significantly in terms of their innovative capacity: the former have been able to gain and maintain world leadership in innovation and technology while the latter continues to lag. Notwithstanding the magnitude of this innovation gap and the political...

This paper argues that existing models of urban concentrations are incomplete unless grounded in the most fundamental aspect of proximity; face-to-face contact. Face-to-face contact has four main features; it is an efficient communication technology; it can help solve incentive problems; it can...