Bottlenecks: only fixing the constraint raises throughput
Every flow has one stage that sets the pace. Improving any other is waste. Find the bottleneck in the experience below and watch throughput jump when you get it right.
A flow has 3 stages: Analysis, Development and Test. 3 items arrive per day. Set each stage’s capacity (how many items it finishes per day), run the simulation and discover what really governs delivery.
What a bottleneck is
A bottleneck is the lowest-capacity stage of a flow. It sets the throughput of the whole system: no matter how fast the other stages are, nothing delivers faster than the bottleneck can process.
Why only the bottleneck matters
Reinforcing a stage that is not the constraint only creates idle capacity: the queue keeps building before the bottleneck and lead time does not change. That is the Theory of Constraints: improve the constraint and the whole system’s throughput rises. Then the constraint moves elsewhere, and you repeat.
How Kanban helps
By making flow visible and limiting WIP, Kanban surfaces the bottleneck: the queue piles up before it. You stop optimizing isolated stages and start attacking what actually limits delivery.
Frequently asked questions about bottlenecks
What is a bottleneck in a flow?
The lowest-capacity stage: the one that sets the throughput of the whole system. Improving other stages does not raise throughput.
How do I identify the bottleneck?
Where the queue builds up and utilization sits at ~100%. In Kanban, WIP piles up before the bottleneck, making it visible.
Why not optimize every stage?
Because system throughput is capped by the constraint. Extra capacity outside the bottleneck sits idle: it is waste.
What happens after improving the bottleneck?
The constraint moves to another stage. You repeat the cycle: identify, improve, follow the new bottleneck: continuous improvement.
Master flow in practice
Manage a whole squad in the Kanban Game.
