Body of Knowledge · Techniques and Models
Brooks's law
Adding people to a late software project makes it later, because the existing people must train the new ones and the communication paths multiply.
Evidence grade: practice A widely adopted practitioner model with clear provenance.
Use it when
Whenever "add people" is proposed for work that is already late; deciding whether more resourcing is a real option early enough to help.
Where it stops working
It applies to work that cannot be partitioned. The judgment lies in telling that work apart from work that can.
Where the standard uses it
- DE-2Estimation, planning, and honest commitmentsManaging uncertainty rather than chasing accuracy.
Sources
- Frederick P. Brooks Jr. The Mythical Man-Month: Essays on Software Engineering. Addison-Wesley, 1975. In the bibliography
Used alongside it
- Batch size and predictability practice
- Cycle time and historical forecasting practice
- The cone of uncertainty practice
- The planning fallacy research
Cite this model
Chicago, BibTeX and licence →Engineering Management Academy. (2026). Brooks's law. In Engineering Management Academy Body of Knowledge (Version 3.1, TEC.brooks-s-law). https://www.engineeringmanagement.academy/body-of-knowledge/techniques/brooks-s-law