Florida compiles the rankings of five major indexes which gauge the relative economic strengths of global cities and metro areas based on different factors, including his own Global Economic Power Index, to determine his definitive list.
"New York stands atop the crowd, finishing first on three of these lists, second on two, and the only city to finish gold or silver in each survey. London is second overall, with one first place finish, two seconds, a third, and a fourth. Tokyo is third. This stands in contrast to my own earlier estimates that had Tokyo placing first, mainly because of the size and diversity of its regional economy, which includes a vast array of manufacturing as well as R&D. Still, both New York and London have considerably more global economic and financial influence," notes Florida.
"There are several reasons to believe New York's position atop the global urban hierarchy is secure, at least for the medium-run. For one, it is the world's most open and diverse large city. With the possible exception of Hong Kong, Asia's cities still lack this level of openness and attractiveness. And they face considerable competition with each other for regional, never mind, global dominance."