Innovation and technological change are central to the quest for regional development. In the globally-connected knowledge-driven economy, the relevance of agglomeration forces that rely on proximity continues to increase, paradoxically despite declining real costs of information, communication and transportation. Globally, the proportion of the population living in cities continues to grow and sprawling cities remain the engines of regional economic transformation. The growth of cities results from a complex chain that starts with scale, density and geography, which then combines with industrial structure characterised by its extent of specialisation, competition and diversity, to yield innovation and productivity growth that encourages employment expansion, and further urban growth through inward migration. This paper revisits the central part of this virtuous circle, namely the Marshall-Arrow-Romer externalities (specialisation), Jacobs externalities (diversity) and Porter externalities (competition) that have provided alternative explanations for innovation and urban growth. The paper evaluates the statistical robustness of evidence for such externalities presented in 31 scientific articles, all building on the seminal work of Glaeser et al. (1992). These articles yield 393 estimates of those externalities, which are characterized by their sign and statistical significance. We aim to explain variation in estimation results using study characteristics by means of ordered p

part of economies of agglomeration in which there is an emergence of economies of scale at the firm level, transport costs and the mobility of the industrial A slum is a highly populated urban residential area consisting of densely packed housing units of weak build quality and often associated with poverty. The infrastructure in slums is often deteriorated or incomplete, and they are primarily inhabited by impoverished people. Although slums are usually located in urban areas, they can be located in suburban areas where housing quality is low and liv The formation of slums is closely linked to urbanization. In 2008, more than 50% of the world's population lived in urban areas. In China, for example, it is estimated that the population living in urban areas will increase by 10% within a decade according to its current rates of urbanization. The UN-Habitat reports that 43% of urban population in developing countries and 78% of those in the least developed countries are slum dwellers. Some scholars suggest that urbanization creates slums because local governments are unable to manage urbanization, and migrant workers without an affordable place to live in, dwell in slums. Rapid urbanization drives economic growth and causes people to seek working and investment opportunities in urban areas. However, as evidenced by poor urban infrastructure and insufficient housing, the local governments sometimes are unable to manage this transition. This incapacity can be attributed to insufficient funds and inexperience to handle and organize problems brought by migration and urbanization. In some cases, local governments ignore the flux of immigrants during the process of urbanization. Such examples can be found in many African countries. In the early 1950s, many African governments believed that slums would finally disappear with economic growth in urban areas. They neglected rapidly spreading slums due to increased rural-urban migration caused by urbanization. Some governments, moreover, mapped the land where slums occupied as undeveloped land. Another type of urbanization does not involve economic growth but economic stagnation or low growth, mainly contributing to slum growth in Sub-Saharan Africa and parts of Asia. This type of urbanization involves a high rate of unemployment, insufficient financial resources and inconsistent urban planning policy. In these areas, an increase of 1% in urban population will result in an increase of 1.84% in slum prevalence. Urbanization might also force some people to live in slums when it influences land use by transforming agricultural land into urban areas and increases land value. During the process of urbanization, some agricultural land is used for additional urban activities.…

In models of monocentric cities, property prices must decrease proportionally with the distance from the city center to compensate for the increase in the cost of transportation (as demonstrated in the pioneering work of Alonso [1960] or Fujita [1989]). In traditional models, costs of transportation are assumed to be known and fixed. However, the gas prices can be fluctuant and thus significantly change the costs of transportation for households and their living expenses. In a zone that is characterized by limited access to employment, a household faces a greater uncertainty in transportation expenses during recessions especially if they have to search out other employment opportunities in the case of being fired. They may take this into account when renting or purchasing a property. In following Scafuri(1984), bid functions can be derived as a function of expected transportation cost and variance. Using time series, for housing and transportation price in personal vehicles in France, we test whether the difference in prices between city center and suburb vary in congruence with expected transportation costs and their volatility. A vector error correction model (VECM) is estimated. The estimated results indicate the existence of a co-integrated relationship: the differences in price between the center and the suburb tend to grow with the volatility of transportation costs. The results bring the first empirical elements that confirm the importance of the uncertainty of transpo

studies the production, distribution, and consumption of goods and services within economies. economies of agglomeration The major subfield of urban economics This glossary of economics is a list of definitions containing terms and concepts used in economics, its sub-disciplines, and related fields. ec…