synergies<sup>6</sup> . The Globalization and World Cities (GaWC) Network identifies 122 “world cities” (see Annex 2, section 10). The measures used to identify ‘world cities’ focus on international transactions. They do not necessarily reflect a city’s ability to develop or capitalize upon these linkages.

A key role for cities and the main impetus behind their formation is the enlargement of local economies which simultaneously enable the specialization of services and the creation of a wide web of exchanges. Only a sufficiently dense and large enough population can support specialized services such as a thoracic surgeon, a nuclear physicist, a retail outlet for fashionable handbags or wine and cheeses from around the world. As urbanization continues, a system of cities will increasingly specialize within the global commercial framework. Different sized cities may specialize in pharmaceuticals, or post-secondary education, or act as a regional transportation hub or financial center. The larger cities will try to keep enough diversification to render their economies flexible and ready to adapt to new changes or intellectual creation. The challenge and wonder of cities is that they are both the contributors to economic activity and progress of civilization, and the providers of basic services for residents, households, firms and governments. Usually the best service providers are also the best economic performers.

Cities also need to provide safe-spaces for their residents. Crime, natural disasters, environmental degradation, and poverty are taxing many cities. A city’s response usually requires a balance between short-term imperatives and long-term social marketing.

Finally, cities are the most tangible level of government for mediation between the rights of an individual and the aspirations of society. Cities are therefore the essential element of democracy. For example, Canada’s new same-sex marriage legislation was catalyzed by the City of Toronto’s actions. Without cities to generate ideals and promote debate, it would be difficult to visualize a democratic society.

Unfortunately, there is no clear definition of a “city”. Cities are often defined as areas with significant population density and self-government. They have distinct administrative, economic and geographical boundaries and these areas often do not coincide. They often comprise “urban agglomerations” and in large metropolises, the city center could be itself an agglomeration. The most common setting is a large urban agglomeration comprising several cities and their suburban fringes.

City definitions differ across countries. In the design of city indicators to be comparable on a wide scale, agreement is needed on the criterion that defines a city or urban agglomeration, which would be the specific unit of analysis. Developing city indicators is especially challenging in metropolitan areas where the internationally recognized city can be made up of many municipalities. City performance indicators may therefore vary from urban performance indicators, as the term ‘urban’ will encompass spatially enlarged units. How best to reflect city indicators in cities and their respective urban areas will be an important aspect of this upcoming work plan.

# **3. The Need for Indicators**

## **3.1. Capturing City Trends**

> 6 Globalization and World Cities (GaWC) – www.lboro.ac.uk/gawc

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