Fred Brooks observed in The Mythical Man-Month (1975) that adding more developers to a project that is already behind schedule will only delay it further.
Why?
- Ramp-up time: New developers must learn the codebase
- Communication overhead: With n people, there are n(n-1)/2 communication channels
- Task partitioning: Not all work is parallelizable
This is one of the most cited laws in tech engineering and remains as relevant today as it was 50 years ago.