The progress function in the aerospace industry — A historical analysis

The progress function is a predictive model developed by the airframe industry in the 1930's. It is also called the “improvement curve” or the “learning curve.” It reflects the relationship between gross production output and the effect required to produce each unit of production. The history of these curves in the airframe industry is reviewed. Modifications of the basic function are examined. Seven major uses of progress curves by the aerospace industry are 1) cost estimates, 2) scheduling, 3) efficiency comparisons, 4) procurement and subcontracting, 5) facilities planning, 6) personnel planning and 7) long-range planning. An evaluation is made of current usage.