Motivation: Reduce Training Time

In The Mythical Man-Month, Brooks states his law: "Adding manpower to a late software project makes it later" [Brooks1975]. He believes that communication costs are the major reason that adding manpower to a late project makes it later. Brooks breaks these communication costs into training and intercommunication. Certainly, reducing training costs is a worthy objective.

Traditionally, people new to an organization are shown different parts of a system by senior staff personnel. This dedicated training time costs the senior personnel valuable hours. During these hours, neither the new person nor the trainer is contributing to the completion of the project. Through pair programming, the trainer teaches by doing (not showing), and direct contributions are made during the training time. Additionally, training seems to go much faster, and the new person learns the system much better.