It is reported in the evening edition of today's Nikkei Newspaper that, according to a Swiss bank's survey, London is the world's most expensive city, to be followed by New York, Oslo, Tokyo, Zurich, Copenhagen, Geneva, Dublin, Chicago and Los Angeles in that order. The main reason why London and New York are most expensive is because of high rents and utility costs in those cities. On the other hand, it was widely reported a couple of months ago that a U.S. consulting company published a ranking of most expensive cities in the world, where Moscow is the most expensive city, to be followed by Seoul, Tokyo, Hong Kong, etc. According to this survey, none of the U.S. cities makes it to top 10. Why is there such a big difference in ranking? A possible reason is that rents can be very different depending on which part (location) of the city to be adopted for the city's "representative" rent level. The central (or the best) location of the city is very different from its suburban (or average) location in terms of housing cost. So, the relative weights attached to rents and other costs could change drastically, affecting the ranking result substantially. Don't be misled by unscientific rankings of this kind anyway.