You're not seeing the wood for the trees. Ireland is just one example among many where it is a poor predictor of growth. I could pick out China, India, Brazil (and complain about the weighting given to small countries), or just point at...all of the data:

http://www.leftbusinessobserver.com/Freedom1996.gif

It's comically bad. Random things like penis size correlate better with economic growth http://static1.businessinsider.com/image/5008876deab8ea62620...

(that's from a real paper from the Helsinki Center of Economic Research, btw, though it's obviously tongue in cheek)

Even its correlation with GDP is pretty shaky: http://www.heritage.org/index/book/images/in-2014-chapter-1-...

This is nothing but a list to write press releases around. There is no science to it, and we shouldn't take it any more seriously than articles about the mathematical formula for the perfect sandwich.