Cumulative Flow Diagram
A Cumulative Flow Diagram (CFD) is a stacked area chart that shows the number of work items in each workflow stage over time, used to monitor flow, identify bottlenecks, and track work in progress.
Explanation
The CFD plots time on the X-axis and the cumulative count of work items on the Y-axis, with each workflow stage represented as a colored band. The width of each band at any point in time shows the number of items in that stage (WIP). The vertical distance between the top and bottom bands at a given time shows total scope, and the horizontal distance shows approximate lead time.
The CFD is a powerful diagnostic tool. If a band is widening over time, it indicates a bottleneck at that stage. If the top line is rising faster than the bottom line, scope is growing faster than the team can deliver. A healthy CFD shows bands of consistent width with the completion rate roughly matching the arrival rate.
CFDs are commonly used with Kanban to monitor overall system health. They complement WIP limits by showing trends over time rather than just the current state. Teams review CFDs during retrospectives or flow review meetings to identify systemic issues.
Key Points
- •Stacked area chart showing items in each workflow stage over time
- •Band width indicates WIP at each stage; widening bands signal bottlenecks
- •Horizontal distance between arrival and completion shows lead time
- •Used to diagnose flow issues and validate WIP limit effectiveness
Exam Tip
If a CFD shows a widening band in one stage, it indicates a bottleneck. The team should investigate why items are accumulating in that stage.
Frequently Asked Questions
Related Topics
Kanban
Kanban is a lean method for managing and improving work across systems that emphasizes visualizing the workflow, limiting work in progress, managing flow, and making process policies explicit.
Work in Progress (WIP) Limits
Work in Progress (WIP) Limits are constraints placed on the number of work items allowed in each stage of a workflow at any given time, designed to improve flow and reduce multitasking.
Burndown Chart
A Burndown Chart is a graphical representation of work remaining versus time in a Sprint or release, showing whether the team is on track to complete the planned work.
Information Radiators
Information Radiators are highly visible displays of project information placed in prominent locations where the team and stakeholders can easily see them, promoting transparency and communication without requiring active effort.
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Burndown Chart
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Relative Estimation is an agile technique where work items are sized in comparison to each other rather than in absolute units like hours or days, providing faster and more accurate estimates.
Sprint Review
The Sprint Review is a Scrum event held at the end of the Sprint where the Scrum Team presents the Increment to stakeholders, gathers feedback, and collaborates on what to do next.
Sprint Backlog
The Sprint Backlog is the set of Product Backlog items selected for the Sprint, plus the Sprint Goal and the plan for delivering the Increment.
Timeboxing
Timeboxing is the practice of allocating a fixed, maximum amount of time for an activity, after which the activity stops regardless of whether it is complete.
Resource Leveling
Resource leveling is a resource optimization technique in which adjustments are made to the project schedule to keep resource usage at or below a defined limit, often resulting in a longer project duration.
Risk Register
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Stakeholder Mapping
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Cost Performance Index (CPI)
Cost Performance Index (CPI) is an EVM efficiency metric that measures cost performance as the ratio of earned value to actual cost: CPI = EV / AC.
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