By John S. McClenahen Unless you're an economic masochist, you can't be thrilled with the latest forward-looking data from the Conference Board. For August, the New York-based business-research group's closely watched index of U.S. leading economic indicators fell 0.2%, twice what economists generally were expecting. The index, an indicator of where the U.S. economy is likely to be in three to six months, now stands at 111.8 (1996 = 100). August is the third consecutive month in which the index has fallen, with seven of the 10 measures that make up the index, including initial claims for unemployment insurance and new factory orders for consumer goods, posting negatives for the month. Only the nation's money supply adjusted for inflation, the average weekly number of manufacturing hours, and stock prices registered gains. However, Jerry J. Jasinowski, president of the Washington, D.C.-based National Association of Manufacturers, suggests August's drop in the leading index "most likely reflects a one-time correction to strong manufacturing output in previous months." Jasinowski notes that during May, June and July, U.S. manufacturing production increased at an average annual rate of 6%, which he characterizes as "an unsustainable pace given the modest pace of the overall recovery."