“Real economists don’t talk about competitiveness,” said Paul Krugman, a much-respected contemporary economist. Real businessmen and real politicians talk about it all the time, however. Many firms have undergone savage downsizing to remain competitive, and governments have set up numerous committees to examine how to sharpen their countries’ economic performance. Mr. Krugman’s objection was not to the use of the term competitiveness by companies, which often do have competitors that they must beat, but to applying it to countries. At best, it is a meaningless word when applied to national economies; at worst, it encourages protectionism. Countries, he claimed, do not compete in the same way as companies. When two companies compete, one’s gain is the other’s loss, whereas international trade, Mr. Krugman argued, is not a zero-sum game: when two countries compete through trade they both win. Yet measures of national competitiveness are not complete nonsense. A country’s future prosperity depends on its growth in productivity, which government policies can influence. Countries do compete in that they choose policies to promote higher living standards. Even so, conceptual and measurement difficulties mean that the growing number of indices purporting to compare the competitiveness of different countries should probably be taken with a large pinch of salt.