Transparency International Corruption Index
This resource is a must for getting a general sense of levels of corruption (and implied cultural acceptance) in different parts of the world. When advising clients who are setting up new programs in places they've never worked before, I always point them toward Transparency International to set some baseline expectations.
Research by Dan Ariely has shown that dishonesty is highly contagious (this will be the subject a future post). Knowing about corruption levels ahead of time can help prevent unexpected and unpleasant surprises.