Giacomo A. M. Ponzetto

Clusters of entrepreneurship

Employment growth is strongly predicted by smaller average establishment size, both across cities and across industries within cities, but there is little consensus on why this relationship exists. Traditional economic explanations emphasize factors that reduce entry costs or raise entrepreneurial returns, thereby increasing net returns and attracting entrepreneurs. A second class of theories hypothesizes that some places are endowed with a greater supply of entrepreneurship. Evidence on sales per worker does not support the higher returns for entrepreneurship rationale. Our evidence suggests that entrepreneurship is higher when fixed costs are lower and when there are more entrepreneurial people.

Cities, Skills, and Regional Change

Glaeser E. L., Ponzetto G. A. M. and Tobio K. Cities, skills and regional change, Regional Studies. One approach to urban areas emphasizes the existence of certain immutable relationships, such as Zipfs or Gibrats law. An alternative view is that urban change reflects individual responses to changing tastes or technologies. This paper examines almost 200 years of regional change in the United States and finds that few, if any, growth relationships remain constant, including Gibrats law. Education does a reasonable job of explaining urban resilience in recent decades, but it does not seem to predict county growth a century ago. After reviewing this evidence, a simple model of regional change is presented and estimated, where education increases the level of entrepreneurship. Human capital spillovers occur at the city level because skilled workers produce more product varieties and thereby increase labour demand. It is found that skills are associated with growth in productivity or entrepreneurship, not with growth in quality of life, at least outside of the West. It is also found that skills seem to have depressed housing supply growth in the West, but not in other regions, which supports the view that educated residents in that region have fought for tougher land-use controls. Evidence is also presented that skills have had a disproportionately large impact on unemployment during the current recession.

Case Law versus Statute Law: An Evolutionary Comparison

Case law develops gradually through the rulings of appellate judges who have heterogeneous preferences but are partially bound by stare decisis. We show that its evolution converges toward more efficient and predictable legal rules. Since statutes do not share this evolutionary property, case law is the best system when the efficient rule is time invariant, even if the legislature is more democratically representative than individual judges are. In the presence of social change, the ideal legal system includes both legislation and judicial decisions as complementary sources of law. Our model thus explains the modern history of common law and the observed cross‐country correlation between legal origins and economic outcomes. It also predicts the gradual convergence of civil law and common law toward a mixed system.

Did the Death of Distance Hurt Detroit and Help New York

Urban proximity can reduce the costs of shipping goods and speed the flow of ideas. Improvements in communication technology might erode these advantages and allow people and firms to decentralize. However, improvements in transportation and communication technology can also increase the returns to new ideas, by allowing those ideas to be used throughout the world. This paper presents a model that illustrates these two rival effects that technological progress can have on cities. We then present some evidence suggesting that the model can help us to understand why the past thirty-five years have been kind to idea-producing places, like New York and Boston, and devastating to goods-producing cities, like Cleveland and Detroit.

Urban networks: Connecting markets, people and ideas

Should China build mega-cities or a network of linked middle-sized metropolises? Can Europe’s mid-sized cities compete with global agglomeration by forging stronger inter-urban links? This paper examines these questions within a model of recombinant growth and endogenous local amenities. Three primary factors determine the trade-off between networks and big cities: local returns to scale in innovation, the elasticity of housing supply, and the importance of local amenities. Even if there are global increasing returns, the returns to local scale in innovation may be decreasing, and that makes networks more appealing than mega-cities. Inelastic housing supply makes it harder to supply more space in dense confines, which perhaps explains why networks are more popular in regulated Europe than in the American Sunbelt. Larger cities can dominate networks because of amenities, as long as the benefits of scale overwhelm the downsides of density. In our framework, the skilled are more likely to prefer mega-cities than the less skilled, and the long-run benefits of either mega-cities or networks may be quite different from the short-run benefits.

Globalization and Political Structure

The first wave of globalization (1830-1914) witnessed a decline in the number of countries from 125 to 54. Political consolidation was often achieved through war and conquest. The second wave of globalization (1950-present) has led instead to an increase in the number of countries to a record high of more than 190. Political fragmentation has been accompanied by the creation of peaceful structures of supranational governance. This paper develops a theoretical model of the interaction between globalization and political structure that accounts for these trends and their reversal. We show that political structure adapts to steadily expanding trade opportunities in a non-monotonic way. Borders hamper trade. In its early stages, the political response to globalization consists of removing borders by increasing country size. War is then an appealing way of conquering markets. In its later stages, however, the political response to globalization is to remove the cost of borders by creating international economic unions. As a result, country size declines and negotiation replaces war as a tool to ensure market access.