Cumulative Flow Diagrams And Bottleneck Theory

Cumulative Flow Diagrams & Bottleneck Theory

1. Introduction to CFD

• CFD stands for Cumulative Flow Diagram.
• It is a stacked graph used in Agile projects.
• Shows how much work is completed and in progress.

2. Understanding the CFD Graph

• The bottom section represents completed work.
• The middle sections represent work in different phases (e.g., development, testing).
• The top section represents remaining work.

Example: A CFD starts with 600 points. Over time, the work is completed and moves through phases like development, testing, and deployment.

3. Identifying Bottlenecks with CFDs

• A bottleneck is identified when a section of the graph widens significantly.
• For example, if the development phase is widening but testing is stagnant, testing is the bottleneck.

4. Theory of Constraints

• The bottleneck is the activity immediately after the widest section.
• If testing is not pulling work from development, then testing is the constraint.
• Agile follows a pull system – work should flow smoothly between phases.

Example: In April, very little was deployed. The constraint was in testing, which wasn’t pulling work from development.

5. Little’s Law

• Helps determine how long work takes to complete.
• Based on the size of the queue in the CFD.

6. Exam Tip

• Expect a question with a CFD graph.
• Identify the bottleneck by finding the phase after the widest section.