What is a Cumulative Flow Diagram?
A Cumulative Flow Diagram (CFD) is a visual chart that shows how work moves through your delivery pipeline over time. Think of it as a "health check" for your workflow that reveals patterns you can't see from your regular board view.
How Does It Work?
The CFD stacks different workflow states (like "To Do", "In Progress", "Done") as coloured bands on a chart. Each band's height represents how many issues are in that status at any point in time. As time progresses from left to right, you can see how work accumulates and flows through your process.
What Can You Learn from a CFD?
Bottlenecks: When one band gets wider whilst others shrink, it indicates work is piling up in that status. For example, if your "Code Review" band keeps growing, you know reviews are becoming a constraint.
Flow Consistency: Smooth, parallel bands indicate steady workflow. Bumpy or diverging bands suggest irregular flow patterns that might need attention.
Work in Progress: The total height of all bands shows your overall WIP. Sudden increases might indicate scope creep or too much concurrent work.
Cycle Time Trends: The horizontal distance between when work enters and exits the system shows how long things take to complete.
How Board Rewind Enhances CFDs
Traditional CFDs show you the pattern but not the story. With Board Rewind, you can:
Click any point on the CFD to jump directly to that moment in your board timeline
See exactly which issues were causing bottlenecks or flow disruptions
Understand the context behind flow patterns by watching how work actually moved
Investigate anomalies by rewinding to see what happened during unusual periods
Common CFD Patterns to Watch For
The Expanding Middle: Work enters faster than it's completed, creating growing WIP and longer cycle times.
The Plateau: Work stops flowing into certain statuses, often indicating upstream problems or resource constraints.
The Spike: Sudden increases in one band, usually caused by urgent work, scope changes, or process disruptions.
The Squeeze: One band gets compressed whilst others expand, suggesting that status is processing work faster than expected.
A CFD doesn't just show you what happened—it helps you understand why your delivery performance changes over time and where to focus improvement efforts.