bigMTs saidThis is "perceived corruption" -- perceived by whom? I'd like to see a map depicting national corruption, accounting for the degree of risk to humanity associated with each nation's breed of corruption.
I say that because we're all aware that the slightest degree of fossil-fuel or pharmaceutical or chemical corruption granted under U.S. or Chinese or EU jurisdiction has wide-reaching implications and affects. Also, I imagine, some forms of corruption self-proliferate more readily.
Corruption, by its nature is perceived. While most Americans don't think it is unreasonable for individuals to donate small amounts of money to their chosen candidate, in some European countries the practice has been outlawed.
Similarly tipping in restaurants, a completely normal practice in restaurants to get better service, can be done in different ways. In the US it is done after a meal, while in India it may be done before a meal. This low-level corruption in India is normal, accepted practice, but in the US could easily lead to a fist fight in a bar, as the staff react more quickly to a higher bidder for better service.
This becomes complicated as additional countries on more and more topics, thus the perception in this particular index is based on how a country views itself, since local customs do not always translate with clear simple statistical analyses.