Technical Supplement 3
After studying this technical supplement, you should be able to:
1. Explain the learning curve concept
2. Identify different uses of learning curves in operations management
3. Calculate the estimated time required to do a task for a given learning curve
LEARNING CURVES AND OPERATIONS MANAGEMENT
As people gain experience in doing a task, they usually can do the task more quickly. For example, consider the time it might take someone to wash a car for the first time. Then imagine how that person might be able to wash his car in less time as through repetitions he learns to sequence the tasks more efficiently or ...view middle of the document...
Exhibit 1 graphs the reduction in unit time required to complete a task as a function of the number of times that the task is repeated when the organization has an 80 percent learning rate.
Learning Curve – 80 Percent Learning Rate
The learning curve is also sometimes referred to as an experience curve, a progress function, or an improvement function. Essentially, the learning curve is a mathematical function that can be used to chart the progress of workers as they learn to do their work faster. An operations manager can express the relationship between the amount of time it takes an organization with a learning rate percentage of r to produce the nth item as an equation:
Tn = T1 (nb)
Tn = time required to complete the nth task
r = learning rate percentage
b = ln(r)/ln(2)
Consider the information given in the aircraft manufacturing example above:
T1 = 100 minutes
T2 = 80 minutes
T4 = 64 minutes
What would be the time required to produce the eighth part?
T8 = (100)(8-0.322) = 51.2 minutes since b= ln(0.80)/ln(2) = -0.322
We can verify that this is the correct answer by remembering that the fourth unit required 64 minutes. Since the eighth unit represents a doubling of output beyond the fourth unit, we would expect its task time to be 80 percent of the time required for the fourth unit. Thus, T8 = 64(0.80) = 51.2. This is the same answer given by the learning curve equation above.
Appendix A at the end of this supplement presents a table giving task time values for selected learning rates. The appendix shows that the estimated time for the eighth unit produced on an 80% learning curve is 0.512 times the task time required for the first unit. Again this confirms the result we calculated above.
How much time would be required to produce all eight parts?
Note that the table also gives the total time required to produce a cumulative number of units. In our example, the total time required to produce the first eight parts would be 5.346 X 100 = 534.6 minutes. The average time per part would be 534.6 / 8 = 66.8 minutes.
HOW OPERATIONS MANAGERS USE LEARNING CURVES
The learning curve helps operations managers make task time estimates by accounting for the fact that initial labor requirements usually do not accurately represent future requirements. Learning curves express the effects of improvements in task procedures over time that serve to reduce the time needed to execute a task. Using these curves managers can develop resource requirement estimates that may be used to financially justify the development of a new product or process. However, operations managers must evaluate learning curve expectations carefully. Expectations are based on the skill levels of workers, incentives and rewards for improvement, performance measurements, and other factors. Importantly, an organization’s culture must support learning in order...