Tech clusters like Silicon Valley play a central role for modern innovation, business competitiveness, and economic performance. This paper reviews what constitutes a tech cluster, how they function internally, and the degree to which policy makers can purposefully foster them. We describe the...

We examine variation in the concentration of inventive activity across 72 of North America's most highly innovative locations. In 12 of these areas, innovation is particularly concentrated in a single, large firm; we refer to such locations as "company towns.'' We find that inventors employed by...

The returns to face-to-face interactions are of central importance to understanding the determinants of agglomeration. However, the existing literature studying patterns of geographic proximity in patent citations or industrial co-location has struggled to disentangle the benefits of...

The paper examines whether there is a significant relationship between economic growth and the degree of urban concentration, as measured by primacy, or the share of the largest metro area in national urban population. Is there reason to believe many countries have excessive primacy and how...

We use detailed data from Indonesian cities to study how variation in density within urban areas affects social capital. For identification, we instrument density with soil characteristics, and control for community averages of observed characteristics. Under plausible assumptions, these...

American cities have experienced a remarkable renaissance over the past 40 years, but in recent years, cities have experienced considerable discontent. Anger about high housing prices and gentrification has led to protests. The urban wage premium appears to have disappeared for less skilled...