Free Exchange -- The Economist

When a product is standardized, the product should sell for the same price around the world.  The theory is that sharp business people would take advantage of arbitrage until the prices converged.  In a brilliant article, Mssrs Ashenfelter and Jurajda explore the wage gaps among nations.  

Between 2000 and 2007 America’s McWage rose by 13% while the Big Mac price jumped by 21%, resulting in a net tumble in the BMPH real wage of 7% (see chart, right panel). Meanwhile, the BRICs advanced as McWages grew faster than Big Mac prices. The BMPH jumped by 53% in India, 60% in China and 152% in a Russian economy recovering from financial crisis in 1998. The going has been slower since then. Russia and China managed gains from 2007 to 2011. Most others did not, as food prices rose faster than McWages. Data gathered this summer for the 2012 calculations may show a further slowdown. Bad news for an emerging world still hungry for better living standards.

I think the article should look at the marginal productivity of labor. Also, I think that the data shows how the world economy is working toward equalizing productive factors with wages around the world for a standardized product. Finally, I think the article proves Robert Solow's growth model where mature economies slow while emerging economies catch up.