Cumulative Flow Analysis

Purpose

The Cumulative Flow Diagram (CFD) is one of the most powerful Kanban visualizations. This session teaches the team to read it, diagnose flow problems, and derive improvement actions from the data.

At a glance

How to run

1. Present the CFD (5 min) — Show the current CFD. Explain axes: x = time, y = item count, bands = workflow stages.
2. Read WIP (5 min) — Vertical distance between bands = WIP in that stage. Is WIP stable, growing, or shrinking?
3. Read lead time (5 min) — Horizontal distance between arrival and departure bands = approximate average lead time.
4. Read throughput (5 min) — Slope of the departure band = delivery rate. Is it steady, accelerating, or stalling?
5. Spot patterns (5 min) — Expanding bands = growing WIP (bottleneck). Flat bands = stalled flow (blocker). Converging bands = draining (good or starving?).
6. Derive actions (5 min) — For each pattern, agree on one experiment: lower WIP limit, add capacity, address blocker, etc.

Materials needed

• Cumulative Flow Diagram (generated from the team's Kanban tool)
• Projector or shared screen
• Reference guide for CFD interpretation

Pitfalls & common mistakes

• Not enough data — A CFD needs at least 2–4 weeks of data to show meaningful patterns.
• Confusing bands — Use consistent colours and labels for each stage.
• Over-reacting to noise — Look for sustained trends, not single-day blips.
• No follow-through — Insights without actions are wasted.

Inclusion & accessibility

• Provide a colour-blind-friendly palette for CFD bands.
• Share the diagram in advance so participants can study it.
• Accompany the visual with a data table for screen-reader users.

Variations

• CFD + lead-time scatter plot — Combine both charts for a richer analysis.
• Weekly CFD check — A 10-minute glance at the CFD during the weekly standup.
• Multi-team CFD — Overlay CFDs from multiple teams to spot programme-level bottlenecks.

When NOT to use this

• If the team has fewer than 2 weeks of flow data.
• If the team does not use a Kanban or flow-based approach.

Source & further reading

• Anderson, D. (2010). *Kanban: Successful Evolutionary Change*. Blue Hole Press.
• Vacanti, D. (2015). *Actionable Agile Metrics for Predictability*. ActionableAgile.