Swimlane diagram

A swimlane diagram is a flowchart in which every department, team or role has its own lane. That way you see at a glance who carries out each step and where the work passes from one department to another.

What is a swimlane diagram?

A swimlane diagram is a visual way to map, analyse and improve a process. It is also called a cross-functional flowchart, because it shows how different departments carry out a process together, from start to finish. The name comes from the lanes in a swimming pool: every swimmer stays in their own lane.

Where an ordinary flowchart only shows the order of the steps, a swimlane also shows who is responsible for each step.

What does a swimlane diagram consist of?

• Lanes: each lane represents one department, team, person or role. The lanes usually run horizontally, one below the other, but vertical lanes work too.
• Steps: each step sits in the lane of whoever carries it out. With horizontal lanes, time runs from left to right.
• Symbols: a rectangle for an activity, a diamond for a decision and a rounded shape for start and end. If you want a fixed standard, use BPMN.
• Arrows: these show the sequence. Every arrow that crosses from one lane to another is a handover.

In the example at the top of this article, a quote request passes through four lanes: customer, sales, engineering and finance. The work is handed over to another department six times. Those handovers are exactly where waiting, misunderstandings and errors arise, so that is often where the biggest improvement lies.

How to make a swimlane diagram

Do this together with the people who carry out the process, for example with sticky notes on a wall. They know how it really works, and that often differs from what the procedure says.

What do you use a swimlane for?

• Process analysis: you see the whole process with all its steps, and with it the bottlenecks and waste.
• Process improvement: you find unnecessary steps and handovers, and can simplify tasks or redistribute responsibilities.
• Communication: everyone sees their own role and how it connects to others. That makes the conversation between departments easier. To pin down responsibilities per task even more precisely, combine the swimlane with a RACI matrix.

Advantages and disadvantages

Advantages

• Overview: a clear picture of the steps in the process and who does what.
• Better collaboration: because it is visible who is involved in each step, departments can make agreements more easily.
• Bottlenecks stand out: handovers, waiting points and back-and-forth between departments become obvious.

Disadvantages

• Time: making a good diagram takes time, because you need the right information from the right people.
• Size: a large or complex process gives a large diagram that is hard to read. So start at a high level and only zoom in where needed.
• No times or volumes: a swimlane shows who does what, but not how long it takes or how often it happens. For that, use a value stream map.

Where do you apply a swimlane?

Swimlane diagrams are used in every sector, from manufacturing and healthcare to education and financial services. Wherever a process runs through several departments, they help to streamline the process, improve communication between departments and, in the end, serve the customer better.

Want to learn how to tackle process improvement in your own organisation? Read more about the Green Belt or Black Belt training course.

The video with this article explains what a swimlane diagram is and what it delivers.