Seems like another list whose main purpose is to put the management consulting firm's name into the media/public consciousness through generating a Top X list based on a hodge podge of Western perspective criteria.
And to be fair, it's not a ranking of top or most important cities as they state the list "assesses the extent to which cities are able to attract, retain, and generate global flows of capital, people, and ideas."
And the wild swings from year to year, the forward looking list is quite different.
"Where the Global Cities Index captures current performance, the Global Cities Outlook offers a forward-looking assessment, evaluating how effectively the world’s leading metros are creating conditions for future success."
All of which is to say - I think they missed putting Kitimat BC on this list as they seem to have done a great job of attracting "global flows of capital, people, and ideas".