Formal economic forecasting is usually based on a (1)_____ theory as to how the economy works. Some theories are complicated, and their application requires an elaborate (2)_____ of cause and effect. Others are relatively simple, (3)_____ most developments in the economy to one or two basic factors. Many economists, for example, believe that changes in the supply of money (4)_____ the rate of growth of general business activity. Others (5)_____ a central role to investment in new facilities—housing, industrial plants, highways, and so forth. In the United States, where consumers (6)_____ such a large share of economic activity, some economy believe that consumer decisions to (7)_____ or save provide the principal (8)_____ to the future course of the entire economy. Obviously the theory that a forecaster applies is of (9)_____ importance to the forecasting process it (10)_____ his line of investigation, the statistics he will regard as most important, and many of the techniques he will apply. Although economic theory may determine the general (11)_____ of a forecast, judgment also often plays an important role. A forecaster may decide that the circumstances of the moment are (12)_____ and that a forecast produced by the (13)_____ statistical methods should be modified to take account of special current circumstances. This is particularly necessary when some event outside the Usual run of economic activity has an a (14)_____ economic effect. For example, forecasts of 1987 economic activity in the United States were more accurate when the analyst correctly foresaw that the exchange value of the dollar would (15)_____ sharply during the year that consumer spending would slacken, and that (16)_____ rates would rise only moderately. None of these conclusions followed (17)_____ purely economic analysis they all required judgment as to future decisions (18)_____, an economist may decide to adjust an economic forecast that was made by traditional methods to take account of other unique (19)_____ he may, for example, decide that consumers will (20)_____ their spending patterns because of special circumstances such as rising price of imports or fear of threatened shortages.