There’s a nice piece in the NYT this morning by Nate Silver looking at the lack of correlation between S & P ratings and real-life outcomes. Warning: it’s long.

fivethirtyeight.blogs.nytimes.com

Sample:

Five years ago, if you were an investor looking for guidance on which country’s debt was the safest to invest in, Standard & Poor’s ratings wouldn’t have done much to help you navigate the headwinds of the financial crisis.

Investors now think that Ireland has more than a 40 percent chance of a default or debt restructuring at some point in the next five years. The country is penalized with double-digit interest rates when it wants to borrow money. But in 2006, Standard & Poor’s had Ireland’s debt rated with its top-of-the-line, AAA rating. It didn’t downgrade Ireland until March 30, 2009, long after its financial problems had become obvious, and the price to buy insurance on its debt had increased tenfold from a year earlier.

Spain, which markets now posit has about a three-in-ten chance of default or restructuring, also had a AAA rating, which it maintained until January 2009. Today it still has a AA rating, one notch higher than Japan’s.

Iceland, the tiny country with the oversized banking sector that came perilously close to national bankruptcy, was in 2006 rated AA+, the same rating the United States now has.

Greece, which now appears more likely than not to endure at least a technical default, had debt rated A, lower than most European countries but a reasonably good grade by world standards. It too was not downgraded until January 2009, and its bonds were still rated as investment-grade until March 2010.