Definition
Understanding the Cumulative Flow Diagram
A Cumulative Flow Diagram (CFD) is a type of chart used in project management, particularly in Agile and Lean methodologies. It helps teams visualize the flow of work items (like user stories or tasks) through different stages of a process, from inception to completion.
Structure of a CFD
A CFD consists of several colored bands, each representing a stage in the process. The horizontal axis represents time, while the vertical axis represents the number of work items. The width of each band at any given point in time indicates the number of items in that stage at that time. The total height of the chart at any point is the total number of items in the system.
Benefits of a CFD
- Identifies bottlenecks: A widening band indicates a bottleneck, where work items are entering a stage faster than they’re leaving.
- Tracks progress: Teams can see how many items have been completed and how many are still in progress.
- Improves predictability: By identifying trends, teams can make more accurate predictions about future performance.
- Enhances communication: The visual nature of a CFD makes it easy to communicate status and issues to stakeholders.
Usage Examples
1. A software development team uses a CFD to track the progress of user stories from ‘To Do’, ‘In Progress’, ‘Testing’, to ‘Done’. They notice a widening band in the ‘Testing’ stage, indicating a bottleneck, and take action to address it.
2. A manufacturing firm uses a CFD to monitor the flow of parts through different stages of production. They identify a bottleneck in the ‘Assembly’ stage and adjust resources accordingly.
3. A customer service team uses a CFD to track customer complaints from ‘Received’, ‘Investigating’, ‘Resolving’, to ‘Resolved’. They use the data to improve their service delivery process.
Historical Context
The Cumulative Flow Diagram has its roots in the Lean manufacturing philosophy, where it was used to visualize the flow of materials through a production process. It was later adopted by the Agile software development community as a tool for tracking the progress of work items.
Misconceptions
- A CFD is not a standalone tool, but should be used in conjunction with other Agile practices and metrics.
- A CFD does not show the quality of work done, only the quantity.
- A narrowing band in a CFD is not always a good sign, as it could indicate a decrease in input or an increase in output, which could be due to various reasons.
Comparisons
- Unlike a Burndown Chart, which shows work remaining, a CFD shows work completed, in progress, and incoming.
- Unlike a Gantt Chart, which shows planned versus actual progress, a CFD shows the actual flow of work items.
Related Concepts
- Kanban
- Lean
- Agile
- Bottleneck Analysis
- Process Improvement
