Jeffrey Frankel writes:  When we talk about an economy’s size or power, we are talking about a broad range of questions – and a broad range of interlocutors. From the viewpoint of multinational corporations, how big is the Chinese market? From the viewpoint of global financial markets, will the RMB challenge the dollar as an international currency? From the viewpoint of the International Monetary Fund and other multilateral agencies, how much money can China contribute, and how much voting power should it get in return? From the viewpoint of countries with rival claims in the South China Sea, how many ships can its military buy?
For these questions, and most others involving total economic heft, the indicator to use is GDP at market exchange rates, because what we want to know is how much the renminbi can buy on world markets, not how many haircuts or other local goods it can buy back home. And the answer to that question is that China can buy more than any other country in the world – except the US.