Cumulative flow diagram
A chart showing the number of items in each workflow stage over time, used to visualize bottlenecks, WIP, and flow stability.
What it means
A cumulative flow diagram (CFD) stacks bands representing each workflow stage over time. A widening band signals a bottleneck: work is entering that stage faster than it is leaving.
The CFD is not part of Scrum but is a standard Kanban and lean metric, useful for spotting flow problems that a simple burndown chart would not reveal, since it separates each stage rather than showing only total remaining work.
Common mistakes
Consistent, parallel bands over time indicate stable, predictable flow, while erratic bands often point to inconsistent WIP limits or unpredictable upstream demand.
Example
A widening 'In Review' band on the CFD prompts the team to add a second reviewer to that stage.