A little more than two months ago I read a fascinating opinion piece in the Wall Street Journal by Ronald Bailey, the science writer for Reason. It's called "The Intangible Wealth of Nations" and it utilizes the findings of a new World Bank study to illuminate the reasons why an immigrant is many times more productive in the United States than in his or her home country, simply by being here:

A Mexican migrant to the U.S. is five times more productive than one who stays home. Why is that?

The answer is not the obvious one: This country has more machinery or tools or natural resources. Instead, according to some remarkable but largely ignored research--by the World Bank, of all places--it is because the average American has access to over $418,000 in intangible wealth, while the stay-at-home Mexican's intangible wealth is just $34,000.

But what is intangible wealth, and how on earth is it measured? And what does it mean for the world's people--poor and rich? That's where the story gets even more interesting.

You can read the rest of the article here, and I would urge all our readers to do so. Among other things, it gives you an appreciation for how tremendously lucky we are to live in this country, and why America is such a magnet for immigrants.