Since the early 1980s foreign-exchange turnover has multiplied 33-fold, while rich countries' official reserves have only risen fourfold.

ECONOMIST: Meddling in the currency market

It is also time to put to rest a popular but fallacious view that since central-bank reserves equal only a fraction of the daily turnover on foreign-exchange markets, intervention is merely a drop in the bucket.

ECONOMIST: Interventionist

The WSJ Dollar Index is an attempt to improve on existing indexes by basing its value on actual, up-to-date turnover by all participants in the foreign-exchange market.

WSJ: WSJ, FX Trader Launch Dollar Index