GaWC Research Bulletin 2

". the relationship between economic globalization and urban development is complex, and quite difficult to trace and to validate empirically"

". few of the available data reveal anything about the flows and interdependencies that are at the heart of the idea of world cities as basing points for transnational capitalism"

"As we shall have cause to regret in the course of this analysis [on London as a world city], international comparative data are often extremely difficult or even impossible to obtain. Statistical information is normally designed, collated and presented to serve national rather than international comparative purposes"

INTRODUCTION

This paper describes an applied geography project concerned with measurement and data. This focus is perhaps surprising given applied geography's many sophisticated contributions to problem-solving via systematic analytical modelling since the 1960s. However, we will argue that in the context of contemporary large-scale social change, measurement of trends, and thus the resulting data, has not kept abreast of the social changes they purport to describe. The key problem is that current tendencies towards globalization in many socio-economic activities transcend the states who have been the prime generators of statistics. Whereas in the recent past, data for countries, as collected together in United Nations publications, provided an adequate evidential basis for studying 'international' changes, such data is simply inadequate for describing trans-state processes. One obvious area of research where this is the case is the study of world cities. Our applied geography project addresses this data problem for world cities by proposing a collective solution to measuring the relations among the class of cities which have been identified as either 'world' or 'global' in the literature.

The paucity of relevant data for studying world cities was recognised at the outset of this research area in Korff's (1987: 491) initial critique of Freidmann's (1986) seminal paper. More recently, Short and his colleagues (1996: 698) have again highlighted the problem asserting that '(t)he study of the global urban system is hampered by lack of available data' thus suggesting that, despite the plethora of writing on world cities, little or no progress has been made to confront this crucial issue. In fact, they describe this data deficiency as 'the dirty little secret of world cities research'. The result is that, without the subjects of this research adequately specified, the work of applied geographers and others to suggest policy solutions to the effects of globalization on cities (see part three of Knox and Taylor, 1995) is certainly hampered and may be viewed, academically, as being somewhat premature. It is the purpose of this paper to begin the necessary task of solving the world city data problem so that the evidential basis of this research area can catch up with the exciting theoretical contributions it has made to understanding contemporary social change.

THE NEGLECT OF RELATIONS IN WORLD CITY RESEARCH

A paradox in the literature on world cities is that while the essence of world cities is their relations to each other this has not been a major component of the world city literature (Smith and Timberlake, 1995a and b; Taylor, 1997). The seminal works of both Friedmann (1986, 1995), who first proposed the 'world city hypothesis', and Sassen (1991, 1994a, 1994b) who asserted a triad of 'global cities' (i.e. London, New York, and Tokyo) are indicative of this fundamental defect in the literature. 

Friedmann's "World City Hypotheses"

Friedmann's (1986) 'hypotheses' argue that the 'new international division of labour' is organized through 'world cities'. These cities are unique because they act as 'control centres' for world capital accumulation and consequently gain specific internal economic and social structures. Friedmann (1986) asserts a hierarchy amongst his list of 'world cities' which, while being widely quoted for its pedagogic and heuristic value, is particularly weak because it lacks any evidential basis. While admitting that the hierarchy is 'complex' because of the tendency for many world cities to have particular biases in specialized functions, he nevertheless goes ahead to create a subjective a priori typology of levels. The data problems become even clearer when you look at the changes he makes to the hierarchy over time because he relies on what can be called 'casual empiricism' (see Friedmann, 1995). The central problem with Friedmann's data has not been tackled in subsequent research which has often just taken the form of measuring the attributes of world cities and then ranking them in numerous tables (eg. Brotchie et al., 1995; Daniels, 1993; Drennan, 1996; Llewelyn-Davies, 1997; London Planning Advisory Committee, 1991; Lyons and Salmon, 1995; Nijman, 1996; Sassen, 1994a, 1994b, 1995). The problem with this, as Taylor (1997) has argued, is that to rank with data on attributes says nothing about inter-relations and yet, by definition, a hierarchy is the outcome of relations between constituent elements.

Another key problem with Friedmann's (1986) hierarchy is that it glosses over the complexity of the European system of cities where several relatively small cities (eg. Amsterdam and Zürich) have a disproportionate influence in the world (see Meijer, 1993; Shachar, 1994). Unlike the unified political space of the USA, in which Friedmann writes, European city specialisations combined with numerous national capitals produce an urban pattern that is not obviously hierarchical at all. On most indicators London is the most important city in Europe, but in relational terms how is it connected to other European cities and does that place it at the apex of a hierarchy? With the data sources currently available we simply do not and cannot know the answer.

Sassen's Triad of World Cities

Sassen's (1991, 1994a, 1996) work is particularly important for her careful specification of the nature of global cities. Although she identifies changes in international banking and finance as vital in the emergence of her triad, she contends that world cities are more than just financial centres. For Sassen (1991) finance is just one of a series of advanced producer services which serve to define global cities as post-industrial production sites. This contrasts with Friedmann's (1986) original idea of world cities as general 'command centres' because a concentration of corporate headquarters is not identified by Sassen as an essential component of a city if it is to be classified as a world city. The crucial difference is that for Sassen a world city is the loci for the critical servicing of global capital not just its specific management. However, the power of Sassen's (1991, 1994a, 1994b) analysis is weakened when she comes to consider the question of a global hierarchy. Although much of her discussion is about transactions between cities her data consists of attributes which simply do not reveal whether the triad really does constitute the apex of a new global hierarchy. Overall, Sassen provides a valuable comparative study of global cities with notable findings on parallel changes between New York, London and Tokyo. However, like Friedmann's, her analysis does very little to advance our understanding of relations between cities, a fault which is particularly serious when considering the role of London in a European system of cities.

We have concentrated our literature critique on the seminal works (those which have set the tone of world city research) of Friedmann and Sassen because their works exemplify, and have unwittingly concealed, the empirical deficit of relational data in the study of world cities. The remainder of this paper introduces a research programme to begin the task of rectifying this crucial weakness in our understanding of world cities.

THEORY, MEASUREMENT AND STANDARDIZATION

All measurement and data are the products of theory: from the vast realm of possible information on a topic selections are made based how a problem is theoretically conceptualised. In the research reported below, as well as reading world cities in the Friedmann (1986, 1995) or Sassen (1991, 1994) sense, as 'basing points' or 'global service production' centres, they can be read more fundamentally as process. Here, of course, we are drawing our relational theoretical stance from the more general theory of Manual Castells' (1996) The Rise of the Network Society wherein world cities are constitutive of a broad societal transformation. For Castells (1996), world cities accumulate and hold onto their wealth and power, because of the process "that connects advanced services, producer centers, and markets in a global network" (page 380). Put succinctly, world cities are produced and reproduced by what flows through them (information, knowledge, money and cultural practices, for example), rather than what is fixed within them (i.e. their forms and functions) (see Allen, 1999). We follow Castells (1996) in his assessment that world cities are process, "by which centres of production and consumption of advanced services, and their ancillary local societies, are connected in a global network" (Castells, 1996, 38).

If we wish to take forward Castells (1996) view of world city as process, (re)produced by global networking and connectivity, however, it is vital that relational data are sought to describe his space of flows.¹ Moreover, if we return back to the research agendas set by Friedmann and Sassen, the main reason why world city researchers' have neglected the relations and linkages between world cities is because of both the abundance of data on city attributes and the lack of availability of relevant relational data. Most data collection agencies focus upon attribute data, both because it is easy to collect and because most demands seem to favour information in this format. Furthermore, where relational data is available, it is inadequate for our needs because it primarily covers states - the prime generators of data - and not cities. Thus, there is data on flows between countries, but little on flows between cities located in different countries.

Expressing concerns analogous to ours, Smith and Timberlake (1995a, 1995b) have constructed a typology of inter-city linkages based upon the form (human, information, material) and function (cultural, economic, political, and social) of flows. In this way twelve types of linkage are identified, but as the authors point out, this 'wish list' for world city research only emphasises just how poor existing data sources are in this research field. Generally data on flows between cities are conspicuous by their absence.

There are some major exceptions to this rule. For instance, air traffic flows between cities can be obtained from timetables and a hierarchy produced (Keeling, 1995; O'Connor, 1995; Kunzmann, 1998; Rimmer 1998), and data on postal flows, telephone calls and internet linkages are also available (Marek, 1992; Warf, 1995; International Telecommunication Union (ITU) World Telecommunication Indicators Database) and can be used to explore city hierarchies. However, there is a basic problem with all such data in that it measures general patterns of flow, but does not differentiate the specific flows within those patterns. For example, a measure of general flows into Miami, say telephone calls or airline flights, confuses Miami's role as a world city link between the USA and Latin America with it's roles as a retirement centre and as a major destination for holiday-makers. In short, such general date on flows is of limited value because it conflates world city formation with other and distinctly separate processes. We need data on world city relations which includes measures of world city functions alone.

The problems we have identified with UN publications or other such sources of available data means that to find relational data, and to build up a data bank sufficient to address the crucial need for information on inter-city relations, specific measurements have to be made on a city by city basis. However, the scale of this task, which requires numerous people to collect data on a number of different cities from across the world, is a recipe for informational chaos unless there is a standard approach.

The Globalization and World Cities (GaWC) Research Group and Network² has been set up at Loughborough University with the express mission of encouraging and organizing such standardized data collection. As well as performing the necessary task of providing a central focus for this work, GaWC is concerned to ensure that data is collected in a manner which allows precise comparisons to be made between different cities' relations. This means that measurement methodologies have to be standardized to ensure we do not produce a plethora of separate studies across which data cannot be matched.

Our relational theoretical standpoint for measurement and standardization therefore, is derived not only from Castells (1996) idea of world city as process (space of flows), but also from Friedmann's (1986) 'world city hypothesis' within a changing world-economy and Sassen's (1991, 1994) analysis of the intensity and centrality of global city producer service complexes. Drawing upon these three related theoretical approaches, in our research we have experimented with different ways of measuring world city relations and have found that three methodologies are particularly useful. First, building upon Friedmann's (1986) ideas about the world city and the new international division of labour, we illustrate the generation of large scale relational data to partly address his casual empiricism, through a 'content analysis' of 'business news' which serves as a 'surrogate' measure of relations. Second, by drawing upon both Friedmann's (1986) readings of (im)migration, and Castells' (1996) specific ideas concerning the flow of knowledge and intelligence, embodied within individuals between world cities, we illustrate the generation of inter-city migration data through 'practitioner interviewing' which serves as a 'labour' measure of relations. Third, by focusing upon Sassen's (1991, 1994) analysis of world cities as production sites for advanced producer service activities, we illustrate the generation of relational data through detailed analysis of producer service office locations, which serves as a powerful 'organizational' measure of relations between world cities. These three methodologies have different advantages and disadvantages, but combined complement each other to provide an overall picture of world city relations. We do not propose that these are the only methodologies suitable for this task and we invite other researchers to make further suggestions and contributions. However, if we are to make progress in generating comparable data on world city relations it is imperative that we start with projects, which can be brought together in the way suggested here. Despite the value of our different and distinctive research on world cities the time has come to act as a collective team in at least the measurement part of our work.

Three Methodologies for Measuring Relations

The aim of these methodologies is to facilitate a reorientation of the study of world cities from comparative studies of internal similarities and differences within cities to a study of the relations between cities.

A Surrogate Measure of Relations: Content Analysis of Business News

As previously stated the original 'world city hypothesis' was proposed as an outcome of the identification of the 'new international division of labour' in the 1970s. However, the dilemma is that any attempt to empirically link the rise of world cities to such trends in the world-economy requires longitudinal data on a large scale. Without a tradition of any 'official data' in this field, longitudinal analysis will entail the new collection of data over a number of years. Hence, we have searched for a measurement methodology which enables large amounts of relational data to be collected from easily accessible, long-term sources. Our solution is a surrogate measure which indicates the economic linkages of a city.

Daily business news as reported by a city's newspapers provides a continuous source of information on what a given editor thinks are the salient news stories of the day for a given readership, the city's business community. Thus, by recording place mentions in a sample of business news stories one can derive a surrogate measure of a city's external relations. Content analysis of city newspapers has been used by Pred (1980) in his classic study of changing hierarchical patterns amongst nineteenth century US cities and the credibility of such analysis for contemporary US cities has been affirmed by Taylor (1997). The key point for our concerns here is that newspapers which serve world cities are available in back issues in libraries so that we have a potential source for monitoring changes in inter- city relations in terms of relative place mentions as a quantitative estimate of business salience. It must be emphasised that this is only a surrogate measure, it does not record actual salience but only importance of places as reflected in number and size of news stories. As with all surrogate measures, there will inevitably be some measurement error: for instance in the subjectivity of editorial choice. Of course, the latter is not a free choice, newspapers have to provide information salient to their readers in order to be successful and we can fairly assume that business readers will be particularly cognisant of how well business news sections meet their needs. Given this rationale and the pioneering success of Pred's longitudinal study, we think this data source is the answer to the empirical problem of studying medium-term trends in world city relations.

We illustrate this measurement methodology with a reanalysis of part of the data originally presented in Taylor (1997). For six selected US cities, the front page of the business section of the city's leading newspaper was surveyed for a sample of 24 days in one year (1990).³ Over 4000 references to places were recorded; we focus on the 990 references to the selected six cities themselves. The result is a unique citation matrix showing which cities were deemed to be important to which other cities in terms of the stories editors judged substantial enough for their leading page (Table 1). Once in matrix form there are many analysis possibilities; here we simply scrutinise the data through row and column percentage analyses (Table 2). Three results are reported for each analysis for each city. Overall, nearly half of the references in Table 1 are self-citations (a city's paper referring to its own city) and these can be measured either as percentages of the newspapers' total of references (row analysis) or as percentages of the total references to that city (column analysis). Relations with New York, the dominant city in the data, and to the other four cities are similarly expressed in row and column analyses. We will provide a preliminary interpretion of this data by focusing on New York and Miami.

The first point to make is the sheer dominance of New York in these information flows between US cities. As America's premier world city, we would be surprised if this were not the case but we can now put a quantitative measure on this to facilitate comparison. Despite a modest level of self-referrals from the New York Times this city has by far the largest number of citations. All other newspapers give between a fifth and a half of their city citations to New York: the highest level in two cases and second only to self-referrals in the other three. In terms of other cities referred to by the Times, only Boston and Los Angeles stand out, the former reflecting common regional interests. (We did not set out to find such 'regional' linkages but they are also discernable in Los Angeles-San Francisco relations.)

Much more subtle, but equally clearcut, is the contradictory role of Miami as a world city . Although Miami has by far the lowest place references (only 37) by newspapers from other cities, the Miami Herald is second only to the New York Times in references to other cities. This suggests Miami's business community is interested in what goes on in other cities but other business communities are not interested in Miami. This asymmetry implies two things. First, Miami has a relatively low hierarchical position within the US urban system (low interest from other cities), but, second, it has a particular role as a gateway city (high interest about other cities). This is, of course, consistent with other studies of Miami which emphasis its Latin American links (e.g. Nijman, 1996).

Our example has dealt with just six cities in one country for one year but it should be clear that the potential is there for a much larger study. The basic advantage of this methodology we have already mentioned; it can produce results from easily accessible sources over the long or medium term. For instance, it is feasible to study a set of all world cities from before the rise of the new international division of labour (c. 1970-80) to the present to see if there is evidence for an intensification of global linkages as Friedmann (1986) originally hypothesised. Finally we must reiterate the limitations of this methodology as a surrogate measure. This is not a direct measure of actual relations, the assumption that the place-based information being supplied to a city business community will represent the pattern of economic relations at that time and place is reasonable but nevertheless subject to error as previously noted. Some errors can be partially smoothed out by employing a large enough sample to 'hide' particular editorial quirks. However, the important point is that, as in other areas where direct measurement is difficult or impossible, surrogates are both necessary to advance our understanding and therefore useful as long as they are treated with special critical care.
 

A Labour Measure of Relations: Skilled Inter-City Migration

Studying flows of skilled, or elite, migration, between world cites, is an extremely pertinent measurement for the generation of relational data to empirically ground both Friedmann's (1986) and Castells' (1996) theoretical arguments. Migration was identified as an important factor in the original formulation of the world city hypothesis (Friedmann and Wolff, 1982; Friedmann, 1986). World city formation is a product of migration:

".transnational elites are the dominant class in the world city, and the city is arranged to cater to their lifestyle and occupational necessities .... Immigrant workers give to many world cities a distinctly 'third world' aspect" (Friedmann and Wolff, 1982, 322-23).

".the world city hypothesis is about the spatial organization of the new international division of labour ... World cities are points of destination for large numbers of both domestic and/or international migrants" (Friedmann, 1986, 75).

Our "network society", as Castells (1996) terms it, is very difficult to research in terms of the flows themselves. The materials constituting the network are often commercially sensitive and it is unlikely, as we have previously indicated, that researchers will be able to get below aggregate information flows for communications. However, there is one exception to this situation because information in terms of specific skills and knowledge is embodied quite literally in key employees who move both within and between firms but also, and crucially, between world cities as part of their career trajectories. Information on such movements constitutes a second way in which relations between world cities can be researched. For this measurement, however, we intend to focus upon skilled inter-city migration, rather than low or unskilled migration (which of course is an element of both Friedmann's and Sassen's argument for world city formation). We focus upon the elite because they are the major facilitators of Castells' (1996) spaces of flows.

The corporate nature of the world city means that cities like London, New York, Singapore and Tokyo are the principal repositories for skilled international labour migration within the global economy (Beaverstock, 1994; Beaverstock and Smith, 1996; Findlay et al., 1996; Hamnett, 1995; Sassen, 1994a). The concentration, and circulation, of skilled international labour within transnational corporations (TNCs) office networks have contributed significantly to world city functional primacy, particularly within the advanced producer service sector (Beaverstock, 1996a; Sassen, 1988, 1994a). Skilled international labour migration is now not only a vital ingredient to, and outcome of, being a world city, but it is also a significant factor which is responsible for globalizing and restructuring world city labour markets in situ (Beaverstock, 1994). Accordingly, as skilled international migration is an important functional capacity in which a world city's producer service complex operationalises its global reach, surveys of such migration flows will provide relational data which can help us construct a measure of world city relations.

Official data on migration flows measures inter-nation (i.e. between states) rather than inter-city flows (Beaverstock, 1990a; Findlay, 1988). Therefore, the only way in which data on the latter can be obtained is through a combination of quantitative and qualitative research methods which are focused at either the firm (Beaverstock, 1996a; Johnson and Salt, 1990), or at the migrants themselves (Beaverstock, 1996b). The two main techniques which have been employed to study skilled international labour migration within advanced producer service world city office networks are postal questionnaires and interview surveys with TNC 'Directors of Human Resources'. Each of these two methodologies will be reviewed in turn.

The use of postal questionnaires in this area of research has the same advantages and disadvantages as elsewhere. In particular low response rates and lack of control over the practice of answering leads to concern for the quality of the resulting data. For example, Beaverstock and Smith (1996) used a postal questionnaire to record the magnitude of international emigration and immigration of staff employed in foreign banks and securities houses in the City of London and achieved only a 23% response rate after eliminating replies with numerous incomplete answers. Nevertheless, questionnaires can provide a relatively simple means of collecting basic data to investigate inter-city relations and have been a very successful research tool to measure labour world city relations in other sectors (eg. Findlay et al. (1994) on Hong Kong's migrant doctors).

Most producer-survey labour analyses have used case study interview surveys. Since the mid 1980s, in-depth research undertaken in the advanced producer service sector has been obtained from interview surveys with individual firms, which are then aggregated together into specific sectoral case studies (eg. Daniels, Leyshon and Thrift's (1988) work on accountancy, and McDowell and Court's (1994) analysis of gender relations in merchant banking). With respect to world city office networks, Beaverstock (1990b, 1991, 1994, 1996a, 1996c; Beaverstock and Smith, 1996) has used the same methodological approach to collect data on skilled international migration within advanced producer service firms. For the latter semi-structured interviews were carried out with City of London based British and foreign investment banks because 'face to face' contact with a bank's 'Director of Human Resources' can provide the in-depth information necessary to begin to understand the complex processes that involve migration between that bank's world city offices. Data was collected from nine investment banks (from a sample of 20) by conducting one to two hour taped semi-structured interviews, which were returned to the interviewees' for extra comment and editorial control. By adopting a standard interview schedule for each bank, covering topics such as global organization, migration flows, migration policies, and future business strategies, the researchers were able to aggregate interview material and begin to construct an overall picture of migration within a case study of investment banks.

Using research findings drawn from two surveys of skilled international labour migration within commercial, merchant and investment banks, management consultancies and advertising agencies world city office networks in 1988 (Beaverstock, 1990a, 1994) and merchant and investment banks in 1993 (Beaverstock, 1996c; Beaverstock and Smith 1996), this section of the paper illustrates relations between world cities on the basis of elite migration. In Table 3 the major cities receiving the flow of skilled migrant labour from advanced producer service London headquarters, and major front-office locations, in 1988 and 1993 are shown. For both dates surveyed, several conclusions can be drawn from this relational world city data. First, there is an overriding concentration of flows from London to New York in both data sets, representing 43 and 33 per cents of flows in 1988 and 1993, respectively. Second, and linked to the first when we begin to explore the nature of hierarchical relations, it is clear that the magnitude of flows for both data sets begins to decrease rapidly as we move further down the urban hierarchy. Thus, for these data sets, we can identify very strong relations between London and New York, Hong Kong, Tokyo, Sydney, Paris and Madrid, but very tenuous relations with other European and East Asian Cities (e.g. Frankfurt, Zürich, Lisbon, Athens, Singapore and Seoul). Third, the data indicates the relative insignificance of relations between London and other North American (eg. Toronto, Los Angeles and Chicago), African (eg. Johannesburg) and Latin American (eg. Mexico City and São Paulo) cities.

The principal explanatory factor which accounts for this pattern of labour flows, and therefore the uneven hierarchical relationships between London and other cities, is the spatial organization of the international financial system, and the disproportionate concentration of ancillary producer service (advertising, management consultancy) needed to support it, rather than more general functional characteristics of the world cities themselves. London, New York, Hong Kong, and Tokyo are the major global international financial centres (Reed, 1981, 1983; Thrift, 1987). Hence, as these cities maintain their financial markets with high concentrations of foreign banks, securities houses, and other associated producer services, it is logical that high concentrations of migrant labour will flow between them (Beaverstock, 1994, 1996c).

The main advantage of this method is that the researcher is able to obtain very detailed material on the patterns and processes of globalization. However, the downside of this methodology is that considerable time and effort has to go into achieving data for a relatively small sample of firms. This leaves the results vulnerable to the problem of being too unrepresentative to serve as a measure of general trends and patterns. However, this problem of depth without breadth only emerges where semi-structured interviews are used alone rather than as part of a suite of methodologies, some of which measure broader patterns of inter-city relations.
 

An Organizational Measure of Relations: The Geographical Scope of Producer Services

Our final methodology for gathering relational data focuses upon how advanced producer services have organized themselves to meet the challenge of globally-oriented clientele. This research relates to the new economic geography of services which has focused on the recent growth of producer services, and within them, financial services (see Corbridge, Martin and Thrift, 1994; Daniels, 1991, 1993, 1996; Thrift and Leyshon, 1994). Different sectors of producer services, and the firms within them, have different organizational approaches to inter-city linkages which can be investigated empirically by analysing the structure of head and branch office locations. Although this method does not provide data on the actual transactions of companies, it does reveal their geographical strategies as prime agents in the making of contemporary world cities (see Budd, 1995; Coakley, 1992; Pryke and Lee, 1995; Thrift and Leyshon, 1994). Such data has been used by Meyer (1986), on how Latin American cities have stronger ties to the USA than between each other, Thrift (1987) on how 'international financial centres' use foreign banks in London and selected London companies' international networks, and Daniels (1986) in his comparative analysis of foreign banks in New York and London. More recently such data has been used to explore hierarchical systems of cities. For example, Lynch and Meyer (1992) use law firm branching patterns to suggest a hierarchy among US world cities, and Daniels, Van Dinteren and Monnoyer (1992) use consultancy services to construct an urban hierarchy in Western Europe. It is clear that this type of data provides a solution to the deficiency of relational studies in world city research (Beaverstock, et al.. 1999, 2000; Taylor, et al. 2000).

In contrast to their clients' whose need for commercial secrecy may inhibit open access to locational strategies, producer service firms need to sell themselves in terms of geographical spread of services as a critical element of the marketing of their wares. Sometimes, therefore, information on networks of offices is relatively easy to obtain in promotional material and from a firm's web sites. But in order to build up comprehensive data bases of external office patterns of service sectors, research in this area takes on an investigative mode of operation using various trade sources to identify key players and then collecting the requisite geographical information on company locational organization. However such intensive research is time-consuming because the information can be collected only firm by firm which may require several contacts to find the right person to provide the right data. On occasions when a firm is not forthcoming with the required information the data-gap may be filled by using other more general information sources (which may be old, partial, and difficult to obtain or gain access to) such as that in business and professional directories, trade journals, specialist libraries, and a variety of internet sites. The end result is a variety of forms of data on individual firms. These different quantities of information translate into different scales of measurement. At the minimal end of the spectrum only presence/absence (nominal) data is obtained - the list of cities where a firm has a presence. At the other end of the spectrum data is available on the number of practitioners a firm has in each city providing for interval measurements. In between there are various other types of information (e.g. specification of office regional responsibilities) which allow for ranking (ordinal measurement) a firm's presence amongst cities. In this way information on the organizational links of producer services within a particular city can be accumulated across firms and services to provide invaluable data on the overall external relations of that city. We illustrate this with a study of London based upon 69 producer service firms in accountancy, advertising, banking/finance and law.

Our organizational method of measuring the relations between cities provides information at three levels of analysis. At the level of the firm, different locational strategies can be documented to inform our study of processes of globalization. At the level of the producer-service sector (i.e. aggregating firms by sector), the specific functional differences between cities can be explored. At the level of the city (i.e. aggregating the sectors), the global reach of the key sectors of world city formation can be charted and mapped. We focus upon the latter two below. This requires aggregating the various levels of measurement derived from the data on firms. In practice this means operating at the level of ordinal measurement by converting interval scales to ranks and interpreting presence/absence as ordinal - for details see Beaverstock et al. (1999). Summing levels of office connections across firms shows that for each of the producer services covered by our data, New York is the city London is most linked to in terms of office connections. Using this (unsurprising) result, in Table 4 we have listed all cities which have 80% or more the level of New York's London connections (Level A), and 60-79% (Level B), for each of the four producer services. It is here that the analysis begins to become interesting. First, at the level of the service sectors large contrasts are picked up: accountancy is the most globalized of the services reflecting its corporate concentration with just six big firms dominating the sector (the data was collected in 1997-8 before the latest merger⁴) hence London's high level connections to 42 other cities; in contrast law is the least globalised of advanced producer services and there are only 5 cities which qualify above the 60% threshold; banking and finance are highly globalised, of course, but in this case offices are geographically concentrated thus resembling law; and finally, advertising is more like accountancy featuring 21 cities, here because of the national character of much of the media, capital cities are particularly featured.

Second, in terms of cities, New York is clearly the place to be for firms located in London: none of New York's closest rivals feature at Level A in all four sectors. In Table 5 the cities with major office connections to London are listed by geographical region, the three globalization arenas of northern America, western Europe and Pacific Asia (including Australasia) (see Beaverstock et al. 1999). Cities are scored by summing 2s for Level A positions and 1s for Level B positions. Hence New York scores the maximum 8 (2 each per sector) followed by Brussels with 6 and Hong Kong and Paris both with 5. Fourteen cities scoring 3 and above are featured in Table 5 - all such cities have at least one A and one B level position in Table 4. The regional distribution illustrates the trans-continental scope of London with the globalization arenas evenly represented among the 14 cities with the best office connections to London - with 4 , 6 and 4 cities respectively. This table also illustrates the geographical concentration of globalization, at least as indexed by London's connections - only three Latin American cities and one African city feature in Table 4 and none qualify for entry to Table 5. Furthermore, no Asian cities (treating Istanbul as European, just) outside Pacific Asia feature in Table 4.

The advantages of this type of data, is that it directly measures major investments by advanced producer service firms in offices across other cities. Hence the organisational geographies mirror the pattern of business either actual or expected in one place and time. The main disadvantage of the method is that it only covers a proportion of company linkages: there are contacts used which fall short of the investment in a setting up a new office. In the legal field, for instance, there are many examples of 'indirect presence' where law firms work within international associations or have strategic associations with firms in other cities. Of course, office network data should be used in conjunction with information on other linkages to build up a comprehensive picture of a city's external relations through its advanced producer service industries.

Data Storage: The Global Observatory Internet Archive

The three measurement methodologies described constitute an initial suite of methods to begin the urgent task of providing an evidential basis for world city relations. While the methods each have their specific advantages and disadvantages, they all generate different forms of a relatively rare commodity: trans-state data. Although such data are produced for world cities and other features of globalization within research projects, unlike 'official' statistics, there is no automatic institutional arrangement for trans-state data to be collated, stored and made accessible for other users. Given the labour required to gather and collate trans-state data, this constitutes a massive waste of social science research work. In short, it is important that the fruits of labour-intensive data production in this area are not lost.

The Global Observatory⁵ is a clearing house for such data functioning to both store data and point to where it can be found. It is divided into several major research fields where trans-state data are required of which world cities is one example. It is here that GaWC is located. The basic idea behind GaWC is for it to operate as a network of researchers who use and develop the methods outlined in this paper for their own research projects and graduate teaching programmes as appropriate. Working linkages within the GaWC network may take a variety of forms:

1. Taught Masters projects and dissertations: Here members of the network encourage their students to adopt GaWC methodologies as tools for their projects.

2. Research Masters and PhDs: As above although here we appreciate that GaWC methods would have to be part of a wider thesis, and in the case of a doctorate, would have to be significantly improved, refined and developed in an original context.

3. Research assistants employed using funds from a member's university: This would involve small scale applications of GaWC methods as seed corns for future work.

4. External research funding: This is the prime goal for collaboration using GaWC methods and would be the basis for large-scale trans-state projects.

This paper is an open invitation to join the network. Specific GaWC Research Briefings are available on the GaWC website2 providing explicit instructions on using the methods described above to ensure standardization for comparability. All data collected through the network will be deposited on the Global Observatory thus facilitating comparative relational work. The Global Observatory currently holds data as web pages in tabular form. This has the merit that all the data is there, unconstrained by any assumptions allowing other researchers to examine it from any perspective. However we recognise some serious drawbacks to this technology and propose to develop more user friendly approaches to the data storage and retrieval problem.

The first problem is that of indexing. There are a number of tables that may be relevant to any particular problem. We are likely to index them with reference to our own research agenda and this may make it difficult for others to find them. The second problem is that the tables are one dimensional and most research is going to need data in more than one dimension. Sensible searches are going to need to identify where a particular city stands on a number of criteria, or how the scores on various criteria are related.

We are therefore developing relational database structures which can be interrogated over the web. The data structure will be organised around a keyfield defined as 264 cities which have been selected on the basis of current GaWC research. We are also experimenting with ways of mounting other quantitative and qualitative data. There is a voluntary protocol for use of the data stored on the website to protect the original data collector.

Finally, our ultimate collective goal will be the elimination of a 'dirty little secret' in world city research by the creation of an on-going trans-state data project. This will provide researchers with the evidence to make reasoned judgements on the nature of globalization through analysis of world city relations and hierarchical tendencies.

ACKNOWLEDGEMENTS

This research was funded by both the Economic and Social Research Council (R000222050) and the Faculty of Social Sciences and Humanities, Loughborough University.

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NOTES

1 In his empirical treatment of his space of flows. Castells (1996) does fall prey to the data limitations highlighted in this paper - see Taylor (1999)

2 Information about GaWC is available at the URL http://www.lboro.ac.uk/gawc/. This site also contains GaWC Research Bulletins (Papers about World Cities) and Briefings (Guides to GaWC methodologies).

3 Acknowledge is made to Travis R Longcore and Carmen McWilliams who collected the original data. We would also like to thank Hayden Lorimer, University of Aberdeen, for his experimentation with the use of specialist business newspapers (London's Financial Times and New York's Wall Street Journal) but here there is a problem of these newspapers mixing up non-business stories with business stories - these papers carry general news items for their readers. The result is that the data collector has to make subjective decisions on what stories to include in the sampling. With business sections there is only business news, other news appears in other sections of the newspapers. Hence we do not recommend the use of specialist newspapers for this exercise.

4 On the 1st of July 1998 Price Waterhouse and Coopers and Lybrand merged to form PricewaterhouseCoopers (PwC). This reduction of the 'Big Six' to the 'Big 5' continues the historical trend of increasing concentration in this sector. At the time of writing the rumour circulating the City was that in the future a merger between Deloitte Touche Tohmatsu International and Arthur Andersen was likely (personal source). However, one has to remember that in 1989, the attempt by Price Waterhouse and Arthur Andersen "to merge into the largest accounting firm in the world with 4,642 partners and annual revenues of $5,038 billion failed because of conflicts of interest over clients and, especially important, cultural differences in organization" (Flood, 1995:157).

5 The Global Observatory internet archive is located at the URL http://www.stile.ac.uk/global.html. The observatory has been designed to store trans-state data as a resource for research on global change.