![]() These various percentages provide a point of departure on which to base predictions. These results might be expected since learning is related to people-the fewer the people, the less the capacity for learning. If the ratio is one-fourth assembly and three-fourths machine work, the operation is largely machine-paced, and the slope is around 90 %. If the ratio of assembly to machine work is 50/50, the slope is about 85 %. But when the proportion of assembly work is lower, the downward slope of the curve is not so steep.In such a largely man-paced operation, an 80 % curve is commonly found. In airframe manufacture three-fourths of the direct labor input is assembly the balance is represented by men engaged in machine work.Thus, operations paced by people have steeper slopes than those paced by machines. 2 Further investigation showed that, although operations having essentially the same proportions of labor content have fairly common slopes, other operations differ in characteristics and corresponding slopes of curve. In fact, it was the regular finding of the common slope of about 80 % for fighter, bomber, and transport planes that started speculation about a general theory of learning curves. Nevertheless, the slope of the curve is common to a wide variety of experience. This is simply because of the different ranges of complexity of items. While the learning curve is a universal phenomenon, it has many variations in form for example, there are great variations in the level at which a curve starts (i.e., the cost of the first unit). Such a straight-line relationship is easier to draw and use for prediction purposes. On a double logarithmic chart, however, it is a straight declining line, which reflects a constant rate of reduction (see Exhibit I-B). On an arithmetic chart, with linear coordinates, the relationship is a curve, showing a rapid initial decline that later trails off (see Exhibit I-A). Thus, the rate of learning to assemble aircraft was concluded to be 80 % between doubled quantities. 1 During subsequent years, definitive studies of aircraft assembly showed the following pattern: the fourth plane required only 80 % as much direct labor as the second the eighth plane, only 80 % as much as the fourth the one hundredth, only 80 % as much as the fiftieth and so on. Learning patterns were reportedly first observed for manufacturing operations in 1925 by the commander of the Wright-Patterson Air Force Base in Ohio. Characteristic Curveīefore I demonstrate its application, however, it is necessary to clarify just what I mean by the learning curve. Thus, an understanding of the learning curve becomes of crucial importance to the business manager. ![]() ![]() Wherever people strive to do better, improvements result otherwise, how would progress take place?īy failing to capitalize on this natural phenomenon, managers will not encourage continued efforts once they become convinced that “further improvements are not possible.” Further improvements are always possible over time, so long as people are encouraged, or even ordered, to seek them. The learning curve, I believe, is an underlying natural characteristic of organized activity, just as the bell-shaped curve is an accurate depiction of normal, random distribution of anything, from human I.Q.’s to the size of tomatoes. People do learn, and they learn according to a generally predictable pattern. In this article I will argue that this practice is not only incorrect but costly. Instead, predictions are usually based on assumptions of level performance and constant costs. Although learning curves have been recognized in industries other than aircraft, they have not been as widely accepted. Such continuing improvement was so common in the aircraft industry that it became the normal expectation in the war time mass production of aircraft thus, production and other types of performance were customarily scheduled on some basis of progressive betterment.īut this is not the practice in industry generally. It has evolved from experience in airframe manufacture, which found that the number of man-hours spent in building a plane declined at a regular rate over a wide range of production. The industrial learning curve quantifies such performance. But how many know that the pattern of improvement can be sufficiently regular to be predictive? How many realize that such patterns can characterize, not only individual performance, but also the composite performance of many individuals organized to accomplish a common task? A thing can always be done better not only the second time but each succeeding time by trying.
0 Comments
Leave a Reply. |