Clemens & Sandefur bring the thunder

Oh my.

Foreign Affairs has their exhaustive and incisive takedown of Paul Collier’s “Exodous”

My favorite bit came at the end:

To get a sense of just how big the gains that Collier brushes aside are, consider the following back-of-the-envelope calculation. Assume for a moment that everything Collier says is correct. He argues that there is an optimal level of emigration from low-income countries and that it lies somewhere between Bangladesh’s rate of around four percent, which he deems beneficial, and Haiti’s level of around ten percent, which he deems harmful. Many low-income countries have emigration rates far below four percent. If those rates were raised to four percent, that would mean about 13 million new immigrants (using the World Bank’s definition of low-income countries and its 2010 estimates of cross-country migration numbers). If all of them moved to OECD countries, the foreign-born population of the OECD countries would rise from 12 percent to 13 percent — the same level found in the United States and far below the 20 percent share in Canada and the 27 percent share in Australia.

Those people would move from countries with average annual incomes of about $600 to countries where average incomes are over $30,000, transforming their lives and adding hundreds of billions of dollars to the world economy every year. In other words, even if one concedes Collier’s dubious moral and empirical claims about immigration, his own analysis suggests colossal potential gains from new immigration without substantial offsetting harm. But somehow, in his policy conclusions, Collier preoccupies himself exclusively with restricting immigration.

Can I get an Amen?