Anyone who is interested in the role of the OECD in this issue can look at the Center for Freedom and Prosperity's site at:
http://www.freedomandprosperity.org/Articles/articles.shtml
The OECD's definition of having a "level playing field" with respect to taxes is that all developed countries should have high, European-like, taxes. Futher, they agitate for information sharing so a person who is tax exempt in one jurisdiction will be punished for moving his investments there. They are supporters and defenders of big and Bigger governments.