Cumulative flow diagram (CFD)
A cumulative flow diagram is a stacked area chart showing, for each state in a workflow, how many items are in that state over time. CFDs visualise WIP per state, lead time (horizontal width between arrival and completion), and bottlenecks (states that are growing relative to others).
CFDs are Kanban's primary diagnostic chart. A healthy CFD shows roughly parallel lines: items entering at the same rate as leaving, WIP stable per state. An unhealthy CFD shows divergence: a state that's growing means WIP is accumulating there (bottleneck), a state that's shrinking faster than upstream means the process is starving. The lead time horizontal width is the operational SLA metric; the stability of the bands is the process-health metric. CFDs require accurate state-transition timestamps, which is the part most teams underinvest in.
Related terms
- Kanban
Kanban is a flow-based work-management method, adapted to software by David J.
- WIP limit
A work-in-progress (WIP) limit caps how many items the team can have in flight at once, per workflow stage.
- Flow efficiency
Flow efficiency is the ratio of value-add time to total elapsed time for a case — typically expressed as a percentage.