Brook's law

Adding manpower to a late software project makes it later." by Fred Brooks, author of "The Mythical Man-Month."

 

The extra human communications required to add another member to a programming team is considerably more than anyone ever expects. It of course depends on the experience and sophistication of the programmers involved and the quality of the documentation, which is often sparse.

 

When a new person joins a running team he will initially be of little value because he doesn’t know the system nor the team. Indeed he can slow things down because he drains time from other people as they teach him about these things. The more people you add, the bigger this slow down effect is. Add enough people and the project can come to a big crunching halt. This is the origin for Brook’s Law ("adding people to a late project just makes it later").