Brooks Law

Abstract

The Mythical Man Month attacked the idea that men and months are interchangeable in software engineering. Brook wrote "Oversimplifying outrageously, we state Brooks' Law:"
"Adding manpower to a late software project makes it later."

Factors

Communications Complexity The more people, the more communications complexity.
b people means n(n-1)/2 channels and 2n cliques)

Training new people takes time

Example

Consider a project predicted to take 4 months with 3 men.

However, the design falls behind and takes 2 months not 1! So there are two months (x3 men = 6 man months) left to do work that was originally estimated at 9 man-months

6 men are added to ensure that the project is done in time.

But tTraining takes 1 month so all the 9 man-months must be done in the last month.

However, the work that 3 men could do in 3 months can't be done by 9 men in 1 month (complexity, interdependencies, testing, ...) Hence Brooks law, also stated by himself as "The bearing of a child takes nine months, no matter how many women are assigned."

Brooks Law

Abstract

Factors

Example

Further reading