Fred Brooks was a distinguished American computer architect, software engineer and computer scientist whose major career achievement was managing the development of IBM’s System/360 family of computers and its OS/360 system software. The experiences gained inspired him to write The Mythical Man-Month – an essential read for every aspiring project manager. Its central theme is that adding manpower to a software project that is behind schedule delays it even longer. He goes on to say that the hypothetical unit of work done by one person in one month is a myth and this is often quoted as Brooks’ Law.
Adding manpower to a late software project makes it later.
He pointed out that complex software programming projects often cannot be divided into smaller discrete tasks that can be worked on by individuals without establishing complex communication between them. Indeed, some tasks cannot be subdivided at all and have an inherent duration that cannot be significantly reduced by increasing the number of people working on them. He summed this up thus:
Nine women can’t make a baby in one month.
In his book he also posed the question, How does a large software project get to be one year late? The answer is “One day at a time!”. Incremental slippages eventually accumulate to produce large overall delays and so attention to meeting small individual milestones is needed during all aspects of any project.
Whilst many of his other observations are more applicable to the specialist tasks around IT systems development the takeaways for us are:
- Throwing resources at a project that is falling behind will not always deliver the outcomes you desire. Onboarding and training new resources takes time and managing larger teams generates its own complexities.
- Some tasks cannot be completed more quickly however much effort is applied.
- There should be no surprises when someone announces that a project is significantly behind schedule. A project that is a year late has had 365 opportunities for remedial actions to be taken.