Work-in-progress limits and flow
Constraining how much is in flight so that the most important things finish sooner. A system loaded to full utilisation has unbounded queue times and no capacity to absorb variance. Starting less finishes more, and looking busy is a different thing from being effective.
Evidence grade: practice A widely adopted practitioner model with clear provenance.
Use it when
A team, department or portfolio where everything has been started and nothing ships; whenever "we need more people" might mean "we need less in flight".
Where it stops working
Limits need enforcing at intake, or they become decoration. The slack they create has to be defended as capacity, and must not be harvested as if it were laziness.
Where the standard uses it
- DE-1Prioritisation under constraintSequencing, trade-offs, saying no.
Sources
- Donald G. Reinertsen. The Principles of Product Development Flow: Second Generation Lean Product Development. Celeritas Publishing, 2009. In the bibliography
Used alongside it
- Cost of delay practice
- Portfolio governance practice
- Trade-off transparency practice
- Urgent versus important practice
Cite this model
Chicago, BibTeX and licence →Engineering Management Academy. (2026). Work-in-progress limits and flow. In Engineering Management Academy Body of Knowledge (Version 3.1, TEC.work-in-progress-limits-and-flow). https://www.engineeringmanagement.academy/body-of-knowledge/techniques/work-in-progress-limits-and-flow