Learning Curves

Learning Curves for Estimating

A forecast estimate of the time required to perform a work package or task is a

basic necessity for scheduling the project. In some cases, the manager simply uses

judgment and past experience to estimate work package time, or may use historical records of similar tasks.

Most managers and workers intuitively know that improvement in the amount

of time required to perform a task or group of tasks occurs with repetition. A

worker can perform a task better/quicker the second time and each succeeding

time she/he performs it (without any technological change). It is this pattern of

improvement that is important to the project manager and project scheduler.

This improvement from repetition generally results in a reduction of labor

hours for the accomplishment of tasks and results in lower project costs. From

empirical evidence across all industries, the pattern of this improvement has been

quantified in the learning curve (also known as improvement curve, experience

curve, and industrial progress curve),

For example, assume that a manufacturer has a new contract for 16 prototype

units and a total of 800 labor hours were required for the first unit. Past experience has indicated that on similar types of units the improvement rate was 80 percent. This relationship of improvement in labor hours is shown below:

1. At this point, what would you do if you were the project manager?

2. Was top management acting correctly in developing an estimate?

3. What estimating techniques should be used for a mission critical project such

as this?