Repetitive Learning Cost
Model And Calculator
This calculator requires the use of Javascript enabled and capable browsers. This calculator is designed to give a reasonably accurate model of costs involved with the process of repetitive learning. The concept of the learning curve was introduced to industry for pre-manufactured assemblies in 1936 by T. P. Wright. Wright described a basic theory for obtaining cost estimates based on repetitive production of assemblies. Since then, learning curves (also known as progress functions) have been applied to all types of work from simple tasks to complex jobs. The theory of learning is simple. It is recognized that repetition of the same operation results in less time or effort expended on that operation. For the Wright learning curve theory, the underlying hypothesis is that the direct labor man-hours necessary to complete a unit of production will decrease by a constant percentage each time the production quantity is doubled. If the rate of improvement is 20% between doubled quantities, then the factor known as the learning percent, would be 80% (100-20=80). While the learning curve emphasizes time, it can be easily extended to cost as well. The learning percent is usually determined by statistical analysis of actual cost data for similar products. If that information is unavailable or is not applicable to the process under scrutiny, the following industry guideline is a starting point.
- 75% hand assembly/25% machining = 80% learning
- 50% hand assembly/50% machining = 85%
- 25% hand assembly/75% machining = 90%
or
- Heavy Equipment 85%
- Complex Equipment 80-85%
- Complex machine tools for new models 75-85%
- Construction Industry Pre-Fab 75-85%
- Repetitive electronics manufacturing 90-95%
- Repetitive machining or punch-press operations 90-95%
- repetitive electrical operations 75-85%
- Repetitive welding operations 90%
- Raw materials 93-96%
- Purchased Parts 85-88%
The calculator uses the learning curve to estimate the unit, average, and total effort required to produce a given number of units. Effort can be expressed in terms of cost, man-hours, or any other measure of effort. The calculator can be set to compute the Wright learning curve (generally large processes and complicated operations) or the Crawford learning curve (considered as less technical than the Wright model). The user is required to enter the effort in terms of cost or man-hours required to produce the first unit, the total number of units, and the learning percent. A detailed explanation of the methods that used in these models to compute learning curve values is contained in the textbook "Engineering Cost Estimating," by Phillip F. Ostwald. Be aware that if you select the Crawford method and enter a quantity of 1,000 or more units, the model will calculate approximate values for cumulative average and cumulative total. There is a point of diminishing returns on both of the models used. The Crawford model, being less complex, is approached at 1,000 units while the Wright model is open ended but certainly finite.
Version 8.9.11
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