In 1977, the Harvard Business Review published an article entitled "Global Cities of Tomorrow."
It was about "model cities" for the location of multinational corporations, cities that would play key roles in their respective international regions and the world.
The article was ahead of the curve, in some ways, but a bit high on speculation. It pointed to Paris, Honolulu, and Coral Gables as the global cities of tomorrow. Nor was it entirely impartial: the author was dean of the School of Business at the University of Hawaii.
A few years later, academicians became more serious about world city research. They developed more rigorous definitions of world cities and started to design world city hierarchies that spanned the earth.
Most of the recent and more reliable rankings include 40 to 60 world cities. These cities are hierarchically integrated in a global urban system that functions as sort of a spinal cord of the world economy.
All rankings acknowledge the supremacy of three cities: New York, London and Tokyo. No other city comes even close. These three have global reach and their influence is felt in every continent. Their stock markets are by far the world's largest and their respective geographical positions allow them to divide up the world in three partially overlapping time zones.
To be sure, they are the ultimate seats of corporate power in the most economically advanced regions of the world: New York in the Americas, London in Europe, and Tokyo in East Asia.
But what does the world city pyramid look like at lower levels?
This is where the rankings start to diverge. There are basically two types of hierarchies. The most common one defines world cities on the basis of individual attributes of corporate power and command and control functions.
They measure "world city-ness" in terms of, for example, the number of headquarters of the world's largest industrial companies, banks, law firms and accountancy firms. Other measures include the size of stock markets in terms of capitalization and number of listed foreign companies.
In these rankings, based on command and control, Miami comes in at the lower end. It is not among the so-called secondary world cities (Los Angeles, Chicago, Paris, Frankfurt, Singapore, Osaka) and in many cases not even among tertiary world cities (Atlanta, San Francisco, Boston, Amsterdam, Zurich, Hong Kong).
In a recently published ranking based on the location of corporate headquarters and first-order subsidiaries of the world's largest 100 companies, Miami did not make the top 50.
The second type of hierarchy defines the world city not so much in terms of power attributes, but concentrates on relational characteristics: The centrality of a city in global economic networks and its connections to other cities in the hierarchy.
This can be measured in flows of trade, people, information and money. On these measures, Miami does considerably better and obtains a ranking well within the top 10 (just think about MIA as the biggest airport in the world in terms of the number of airlines with regularly scheduled flights).
In this type of hierarchy, the primary cities have global reach, the secondary cities have a central role in one world region (South America, the Pacific Rim, Europe) and tertiary cities function predominantly at the national level (Zurich, Buenos Aires, Jakarta).
Thus, one branch of the hierarchy, from the top down, would include New York-Miami-Buenos Aires. Other examples would be London-Frankfurt-Zurich and Tokyo-Singapore-Jakarta.
For cities like Miami, it is important to realize the hierarchy based on relational and network characteristics is much less stable than the one based on command and control.
Cities with large numbers of corporate headquarters and big stock markets tend to have long histories. Their roles as world cities are anchored in the urban economy as well as in the global economy.
The relational hierarchy is much more dynamic and world cities come and go at a faster pace. This is exemplified by Miami's rapid ascent.
Other, more recent, spectacular examples are Dublin and Berlin. Is Sao Paulo waiting in the wings? For a world city like Miami, the competitive advantage can never be taken for granted.
Jan Nijman is Professor of Geography in the School of International Studies, University of Miami.