Learning curve calculation
Calculating the learning curve
The cumulative average-time learning model is one of the most commonly used models in learning curve analysis. It calculates the average time or cost per unit based on the cumulative number of units produced.
In a learning curve, the production time decreases as cumulative production increases. For instance, if a company operates with a 70% learning curve, each time the total number of units produced doubles, the cumulative production time for all units drops to 70% of what it would have been if there were no learning effect. In the absence of learning, doubling production would simply double the time required.
The cumulative average-time learning model can be applied to calculate the following metrics:
- Total production time or cost: This is the total time (or cost) required to produce the entire quantity of units, from the first unit to the last. It takes into account the efficiency improvements gained as production increases.
- Cumulative average time per unit: This refers to the average time taken to produce each unit, calculated from the very first unit produced to the final unit in the total quantity. This average reflects the efficiency gained across all units due to the learning process.
Example: See the following summary of production capacities for a company that manufactures model cars. The first unit takes to produce and the company has determined that an is applicable.
In terms of the total production time and incremental time, the following interpretations can be inferred from the table:
- If the company produces only one unit, it will take 20 hours.
- Producing the second unit (the first doubling of production) will take a total of 32 hours, or an additional 12 hours from the original 20 hours it took to produce the first car. As a result, instead of 20 hours, it will only take 12 hours to produce the 2nd car.
- Producing a total of 4 units (the second doubling of the production) will take only a total of 51.2 hours, or an additional 19.2 hours from the first 2 units produced. As a result, 19.2 hours would be the hours required to produce the 3rd and 4th cars.
- Producing a total of 8 units (the third doubling of the production) will take a total of 81.92 hours, or an additional 30.72 hours from the first 4 units produced. As a result, it will take 30.72 hours to produce the 5th to 8th cars.
In terms of the cumulative average time per unit, you will notice that the average time decreased as the production is doubled. By the time 8 cars are produced, the cumulative average time per unit falls to 10.24 hours (), compared with 20 hours for the first unit - keep in mind that this 10.24 hours is the average across all 8 cars, not the time to build the 8th car by itself.
All the calculations above can be represented in the following formula:
Where:
- Y = Total production time (or cost) to produce all units
- a = the time or cost to produce the first unit
- LC = the learning curve in decimals
- n = the number of doublings to date
Applying the formula to the model car example, where is the per-doubling factor and is the time to produce the first car, for the third doubling gives hours, the same cumulative total shown earlier. Keep in mind that is the total production time for all units - to get the cumulative average time per unit, divide by the number of units produced (for example, hours per unit).
The learning curve analysis can manifest in different ways in the exam but the key is understanding the concepts behind it. CMA candidates can be asked about:
- the total production time
- the average time per unit; or
- the incremental time required to produce additional batches.
Let’s take the following example problem:
Example 1: EcoDrive Technologies is launching a new line of electric motors for eco-friendly vehicles. As the production team gains experience, EcoDrive expects a reduction in production time due to improved efficiency. Based on past experience, the company projects an 80% learning curve. The cost to produce the first motor is estimated at $10,000.
Required: What is the estimated cost of manufacturing an additional seven (7) motors after the first one has been completed (8 total units)?
Solution: Manufacturing an additional seven (7) motors mean that production has already doubled thrice from the original one that was produced.
Using the formula:
where:
- is the total cost of producing 8 units,
- , which is the number of doublings at the production level of 8 units
- which is the cost of producing the first motor; and
- which is EcoDrive’s learning curve,
we can compute the total cost of producing 8 units.
This means that if the first unit costs $10,000 to produce, then the cost of the next seven units will be:
The base quantity doesn’t have to be a single unit - it can be a batch, as the next example shows, where is the time to produce the first batch of 100 units, and doublings are counted from that batch.
CMA candidates can also be asked to do a simple estimation of the learning curve percentage like as follows:
Example 2: Nova Robotics took 10,000 hours to produce its first batch of 100 units. When production doubled to 200 units, the total labor time amounted to 16,000 hours.
Required: What is the learning curve percentage of Nova Robotics?
Explanation: The hours without efficiency would have been: .
To calculate the learning curve, divide the time for 200 units (after the efficiency gains) by the time for 200 units (without the efficiency gains): .
Conclusion
Learning curve analysis offers several benefits:
- more accurate labor-cost and pricing estimates for new products
- more realistic budgets and cost standards as production ramps up
- better-informed bid and pricing decisions on new contracts
It also has shortcomings:
- assumes the learning rate stays constant, which rarely holds exactly in practice
- learning levels off once a process matures, so the model works best early in production
- only fits labor-intensive, repetitive work - it doesn’t apply to automated or one-off processes
- staff turnover or process changes can disrupt or reset the learning effect
- the learning curve percentage itself can be difficult to estimate accurately
It is important to recognize the limitations of the learning curve percentage used in these models. The learning curve should ideally be above 50% and below 100%. A percentage of 50% or below would indicate unrealistically high efficiency gains, while a percentage of 100% or higher suggests no improvement at all. Businesses typically use learning curves between 70% and 90% to reflect realistic improvements based on industry and process complexity.



