Should U.S. measure the black market?

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The government announced last week that the U.S. economy shrank in the first quarter. That's the first quarter in the red in three years. It's certainly not catastrophic, but it got me wondering whether the mafia might be able to help on this one. No, I'm not suggesting that organized crime make offers that American CEO can't refuse. Instead, I'm suggesting that the U.S. might want to take a page from Italy's book. Let me explain.

Italy's GDP has essentially the opposite track record of the U.S. until recently. The fourth quarter of 2013 was the first time Italy's economy grew in two years. So Italy dipped into the shadows this past week, the shadow economy, that is.

Starting in 2014 and going retroactively, Italy has said it will add the mafia's dealings to its GDP. And not just like Cosa Nostra, but anyone who makes money in the black market, drug dealing, prostitution, smuggling. Analysts expect this accounting change to boost Italy's GDP a good percentage point or two.

You might laugh, but the black market is a big deal. A 2011 analysis found that if the worldwide black market were a national economy, it would trail only the United States in size, totaling some $10 trillion a year. Another study found that America's underground economic activity was worth about $2 trillion. That's more than 10 percent of the legit GDP.

There are, of course, many other countries reported to have large underground economies, like Russia, where the formal economy is also doing badly these days. In fact, maybe adding the mob to the GDP is the one thing that Washington and Moscow could agree on right now.