MaizeD
I was looking for that, too, but couldn't find the right search terms.
I had it bookmarked for future reference, but my bookmarks got out of hand so one day during computer 'housework', I deleted them all.
It was not, IIRRC, an in depth-study - more a survey - but it threw up some interesting insights into the thinking behind this issue.
The idea that wealthy people simply decide to uproot, lock, sock and barrel, and take themselves and their wealth elsewhere, was not born out by the study / survey.
I do remember that the word 'attachment' was used - it doesn't seem to occur to some that wealthy people do form an attachment to where they live, and have an established way of life, as many ordinary people do, which is quite difficult to abandon.
Obviously, some do just bugger off so to speak but I think the idea promulgated that wealthy people will just up sticks and move to another country is a bit of an urban myth.
A very useful one.