Discussion
Impaler_2019
Stevenson_CH07Supplement_Accessible.pptxSupplement 7
Learning Curves
© McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw-Hill Education.
1
Learning Objectives
You should be able to:
7S.1 Explain the concept of a learning curve
7S.2 Make time estimates based on learning curves
7S.3 List and briefly describe some of the main applications of learning curves
7S.4 Outline some of the cautions and criticisms of learning curves
7S.5 Estimate learning rates from data on job times
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Learning Objective 7S.1
Learning Curves
Learning curve
The time required to perform a task decreases with increasing repetitions
The degree of improvement is a function of the task being done
Short, routine tasks will show modest improvement relatively quickly
Longer, more complex tasks will show improvement over a longer interval
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3
Learning Objective 7S.1
The Learning Effect (1 of 2)
The learning effect is attributed to a variety of factors:
Worker learning
Preproduction factors
Tooling and equipment selection
Product design
Methods analysis
Effort expended prior to the start of work
7S-‹#›
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Learning Objective 7S.1
The Learning Effect (2 of 2)
Changes made after production has begun
Changes in work methods
Changes in tooling and equipment
Managerial factors
Improvements in planning, scheduling, motivation, and control
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Learning Objective 7S.1
Learning
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Learning Objective 7S.1
Interesting Characteristics of Learning
The learning effect is predictable
The learning percentage is constant
Every doubling of repetitions results in a constant percentage decrease in the time per repetition
Typical decreases range from 10 to 30 percent
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Learning Objective 7S.1
Learning Curves: On a Log-Log Graph
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Learning Objective 7S.2
Learning Illustrated (1 of 2)
Each time cumulative output doubles, the time per unit for that amount should be approximately equal to the previous time multiplied by the learning percentage.
If the first unit of a process took 100 hours and the learning rate is 90%:
7S-‹#›
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Learning Objective 7S.2
Learning Illustrated (2 of 2)
| Unit | Unit Time (hours) |
| 1 | = 100 |
| 2 | .90(100) = 90 |
| 4 | .90(90) = 81 |
| 8 | .90(81) = 72.9 |
| 16 | .90(72.9) = 65.61 |
| 32 | .90(65.61) = 59.049 |
7S-‹#›
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10
Learning Objective 7S.2
Unit Times: Formula Approach
7S-‹#›
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Learning Objective 7S.2
Example: Formula Approach
If the learning rate is 90, and the first unit took 100 hours to complete, how long would it take to complete the 25th unit?
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Learning Objective 7S.2
Unit Times: Learning Factor Approach (1 of 2)
The learning factor approach uses a table that shows two things for selected learning percentages:
Unit value for the number of repetitions (unit number)
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Learning Objective 7S.2
Unit Times: Learning Factor Approach (2 of 2)
Cumulative value, which enables us to compute the total time required to complete a given number of units
7S-‹#›
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Learning Objective 7S.2
Example: Learning Factor Approach (1 of 2)
If the learning rate is 90, and the first unit took 100 hours to complete, how long would it take to complete the 25th unit?
7S-‹#›
© McGraw-Hill Education.
Learning Objective 7S.2
Example: Learning Factor Approach (2 of 2)
How long would it take to complete the first 25 units?
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Learning Objective 7S.3
Learning Curve Applications
Useful application areas:
Manpower planning and scheduling
Negotiated purchasing
Pricing new products
Budgeting, purchasing, and inventory planning
Capacity planning
7S-‹#›
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Learning Objective 7S.4
Cautions and Criticisms (1 of 3)
Learning rates may differ from organization to organization and by type of work
Base learning rates on empirical studies rather than assumptions where possible
Projections based on learning curves should be regarded as approximations of actual times
Because time estimates are based on the first unit, care should be taken to ensure that the time is valid
7S-‹#›
© McGraw-Hill Education.
Learning Objective 7S.4
Cautions and Criticisms (2 of 3)
Some of the improvements may be more apparent than real: improvements in times may be caused by increases in indirect labor costs
In mass production situations, learning curves may be of initial use in predicting how long it will take before the process stabilizes
The concept does not usually apply because improvement in time per unit is almost imperceptible
7S-‹#›
© McGraw-Hill Education.
Learning Objective 7S.4
Cautions and Criticisms (3 of 3)
users of learning curves fail to include carryover effects from previous experiences
Shorter product life cycles, flexible manufacturing, and cross-functional workers can affect the ways in which learning curves may be applied
7S-‹#›
© McGraw-Hill Education.
Learning Objective 7S.5
Estimating Learning Rates (1 of 3)
A manager wants to determine an appropriate learning rate for a new type of work his firm will undertake. He has obtained completion times for the initial six repetitions of a job of this type. What learning rate is appropriate?
7S-‹#›
© McGraw-Hill Education.
Learning Objective 7S.5
Estimating Learning Rates (2 of 3)
| Unit | Completion Time (hours) |
| 1 | 15.9 |
| 2 | 12.0 |
| 3 | 10.1 |
| 4 | 9.1 |
| 5 | 8.4 |
| 6 | 7.5 |
7S-‹#›
© McGraw-Hill Education.
Learning Objective 7S.5
Estimating Learning Rates (3 of 3)
According to theory, the time per unit decreases at a constant rate each time the output doubles (e.g., 1 to 2, 2 to 4, and 3 to 6). The ratios of these observed times will give us an approximate rate.
Not surprisingly, there is some variability; the rate is usually a smoothed approximation. Even so, the ratios are fairly close–a rate of 75 percent in this case.
7S-‹#›
© McGraw-Hill Education.
Operations Strategy
Learning curves have strategic implications for:
Market entry when trying to rapidly gain market share
As volume increases, operations is able to move quickly down the learning curve
Reduced cost improved competitive advantage
Useful for capacity planning
Can lead to more realistic time estimates, thus leading to more accurate capacity needs assessment
7S-‹#›
© McGraw-Hill Education.
End of Presentation
© McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw-Hill Education.
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