It's a really difficult thing to assess, isn't it? The criteria (reporoduced below) are pretty arbitrary, really, and can be distorted. My favourite example of this is the fact that google hits was used as a factor and Paris scored higher than London on this primarily due to the existence of Paris Hilton.
I've been to very few of these cities - only London, Barcelona, Paris and Hong Kong. Of the four, only London left me underwhelmed, but that's maybe due to the fact that some of my visits have consisted of just passing through it on the tube en-route to somewhere else. When I stayed there, I found it OK but (as is traditional for a northern Englishman) wouldn't want to live there. I loved Paris though the people didn't seem very welcoming, Barcelona I just loved, and I was blown away by the vibrancy of Hong Kong - my perception of the latter was not doubt affected by being shown round by a Hong Kong Chinese friend and it being the beginning of a wonderful holiday.
I went to (old) York today, and just before Christmas it's absolutely lovely.
Population
Reason for inclusion: sheer scale is the most basic attribute of a city.
Measure: population of the metropolitan agglomeration.
Source: the German website www.citypopulation.de, and local authorities.
Score: one point per million inhabitants, rounded.
Drawback: this is a much tougher proposition than you might imagine, as there is no standard agreement on where to draw the boundaries. As Jon Copestake of the Economist Intelligence Unit says, "Assessing city populations is a contentious and sometimes difficult situation". As a consistent source that included almost all the cities covered, we used the well-regarded website www.citypopulation.de. Figures for the two that are not covered by this impressive survey, Edinburgh and Abu Dhabi, were sourced from the relevant local authorities.
Flights per week
Measure: direct flights departing each week from all the city's airports.
Source: information supplied by OAG (Official Airline Guide), the global flight information and data solutions company.
Score: one point per thousand flights, rounded.
Drawbacks: cities in remote and/or insular locations (such as Auckland and London) will tend to score disproportionately high; those with excellent rail links, such as Paris, have seen many domestic flights displaced by train connections and score lower than they might otherwise.
Stock market value
Measure: market capitalisation of the stock market, in tens of trillions of US dollars, as supplied by the World Federation of Exchanges and individual bourses. For New York, the value of the NYSE, the American Stock Exchange and the Nasdaq were aggregated.
Score: the square root of the "market cap" was taken.
Reason for inclusion: to identify if the city is a significant engine for the economy.
Drawback: in Europe, several bourses have amalgamated, so that Brussels, Amsterdam and Paris share the sum of the Euronext valuation. In addition, cities where a large proportion of economic activity is in the hands of state-run or privately funded enterprises will fail to score as well as they might - if at all.
Ethnic restaurants
Measure: number of non-native restaurants listed in the current Time Out City Guide
Score: one point for every 20 such restaurants; one point if there is no Time Out guide covering the city.
Reason for inclusion: a measure of diversity.
Drawback: the researchers were obliged to make a call about whether a restaurants was "native" or not on the basis of information in a brief review. In addition, many diverse cities are not (yet) covered by Time Out guides. And cities with extremely strong native cuisines, such as Paris and Rome, score disproportionately low.
"Three-star sights"
Measure: in the Michelin Green Guide, how many three-star sights (the top rating) does the city have?
Score: one for each; if a city is covered by a Green Guide but does not have a single three-star sight, then a point is deducted. This is intended to treat fairly cities that are not covered by Michelin.
Reason for inclusion: this is the one measurable quantity of excellence for tourist atractions.
Drawback: ultimately, this is still a subjective call by the compilers of the guides; and cities with outstanding sights that are not covered by Michelin can claim to be losing out.
Capital?
Measure: is the city, or has it ever been, a capital?
Score: two points if the city is currently a capital, one point if it was once but is no longer; incidentally, this was enough to provide the one-point victory by London over New York.
Reason for inclusion: being a political capital increases everything from the prestige to the economic activity of a city.
Drawback: both "is" and "was" are riddled with problems. For example, the world community refuses to recognise Israel's claim that Jerusalem is its capital, and in practice Tel Aviv fulfils so many aspects of a capital city that we have awarded both points to the city. Edinburgh naturally gains a pair of points as capital of Scotland, but Dubai does not get one - even though it the capital of its individual Emirate - because neighbouring Abu Dhabi is officially capital of the whole UAE. Edinburgh "Was" is even trickier: while Rio was plainly the capital of Brazil until Brasilia took the title in the 1960s, a city such as Frankfurt presents a trickier decision. The German economic powerhouse was once a "Free Imperial City" within the Holy Roman Empire, and gains a point for effectively having been capital of itself in the manner of, say, Hong Kong.
Corporate HQs
Measure: the number of companies in the top 50 of the Forbes Global 2000 - "a comprehensive list of the world's biggest and most powerful companies, as measured by a composite ranking for sales, profits, assets, and market value".
Score: one point for each company.
Reason for inclusion: a measure of economic might.
Drawback: Samsung, the company in 48th place, has assets of only $66 billion, compared with Citigroup, which is backed by a handy $1.5 trillion; but each earns the same for the cities of Seoul and New York respectively. In addition, some of the world's biggest firms have headquarters in obscure places; Wal-Mart is based in Bentonville, Arkansas, while Nestle is headquartered in Vevey, a small town on Lake Geneva. Even though much of their financial might is handled in New York and Zurich respectively, these cities do not earn any points.
Symphony orchestras
Measure: how many symphony orchestras does the city have?
Score: one point for one, two points for more than one.
Reason for inclusion: an indication of serious cultural worth.
Drawback: the definition of a "proper" symphony orchestra; and the exclusion of alternative representations of serious music (eg Chinese opera) and other forms of music (eg rock and pop) from the score.
Olympics
Measure: has the city hosted a modern Olympic Games
Score: one point for each time
Reason for inclusion: a mark of recognition as a world-class sporting venue
Drawback: London and Paris, hosted their Olympiads a long time ago (1908/1948 and 1900/1924 respectively) yet still earn two points each.
Google-o-meter
Measure: the number of results, to the nearest million, that you get when you type in the name of the city into google.com (not google.co.uk, which would have a British bias). Measurements were taken between 2.15pm and 2.30pm GMT on 7 December.
Score: the cube root, rounded to the nearest whole number.
Reason for inclusion: the most popular search engine on the world wide web is a good guide to the pre-eminence of a city in the global mindset. Because results vary so sharply, a very strong attenuator is applied, in the form of the cube root of the number.
Drawback: all sorts of factors can distort the score on Google: sites featuring the celebrity Paris Hilton helped push the score for the French capital well above London's.
Underground railway
Measure: length of underground railway in miles. While many cities have mass-transit railways, only relatively few have substantial stretches underground - a mark of substantial investment in infrastructure. The source was the website Urbanrail.net, a fairly comprehensive site of underground networks.
Score: cube root of the length, in miles
Drawback: some cities - Chicago, New York, Paris, London - have stretches of elevated railway that are every bit as good as underground lines, but these were not included. In addition, it was sometimes difficult to assess precisely how much of the system is underground; Mexico City’s result is based on multiplying the total of 125 miles of Metro line by the proportion of the stations that are located underground.
Guidebooks
Measure: the number of individual guidebooks on the shelves of Stanfords in Covent Garden, London
Score: one point for every 10 guides, rounded
Reason for inclusion: tourists, expatriate workers and business visitors all tend to buy guidebooks, and the broader the selection at the world's biggest map and travel guide store, the stronger the interest in the city.
Drawback: this is an Anglo-centric measure; a travel bookstore in New York, Hong Kong or Mexico City would provide very different answers.
48 Hours
Measure: how many times the city has appeared in The Independent's 48 Hours city-break feature in the past seven years (since the start of 2000).
Score: one point for having appeared up to five times; two points for being in the "superleague" of six appearances or more (an honour shared by seven cities: the great European half-dozen of Amsterdam, Barcelona, Berlin, London, Paris and Rome, plus the world's favourite stopover, Singapore).
Reason for inclusion: an indication of the popularity of each city for short-break visitors.
Drawback: the decision on when, and how frequently, a city should appear in the 48 Hours segment, is a judgement firmly focussed on demand among readers of The Independent Traveller; while they comprise a diverse and interesting group of people, they are not representative of the world's population as a whole.
World Heritage Sites
Measure: how many UNESCO World Heritage Sites does the city have?
Score: one for each
Reason for inclusion: this global cultural watchdog applies rigorous criteria before awarding the accolade of World Heritage Site, a badge of historic merit.
Drawback: the entire "historic centre" of a city such as Athens or Rome can comprise a single World Heritage Site, while London has four much smaller sites and scores a point for each of them.
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