Kanban is Japanese for “visual sign” or “card.” It is a visual framework used to implement Agile that shows what to produce, when to produce it, and how much to produce. It encourages small, incremental changes to your current system and does not require a certain set up or procedure (meaning, you could overlay Kanban on top of other existing workflows).
Kanban was inspired by the Toyota Production System and Lean Manufacturing. In the 1940s, Toyota improved its engineering process by modeling it after how supermarkets stock shelves. Engineer Taiichi Ohno noticed that supermarkets stock just enough product to meet demand, optimizing the flow between the supermarket and customer. Inventory would only be restocked when there was empty space on the shelf (a visual cue). And because inventory matched consumption, the supermarket improved efficiency in inventory management.
Toyota brought these same principles to its factory floors. Different teams would create a card (or Kanban) to communicate that they had extra capacity and were ready to pull more materials. Because all requests for parts were pulled from the order, Kanban is sometimes called the “pull system.”
These same ideas apply to software teams and IT projects today. In this context, development work-in-progress (WIP) takes the place of inventory, and new work can only be added when there is an “empty space” on the team’s visual Kanban board. Kanban matches the amount of WIP to the team’s capacity, improving flexibility, transparency, and output.
According to the Kanban blog, “Kanban is a technique for managing a software development process in a highly efficient way. Kanban underpins Toyota's ‘just-in-time’ (JIT) product system. Although producing software is a creative activity and therefore different to mass-producing cars, the underlying mechanism for managing the production line can still be applied.”
When looking at Kanban vs Agile, it’s important to remember that Kanban is one flavor of Agile. It’s one of many frameworks used to implement Agile software development.
A Kanban board is a tool to implement the Kanban method for projects. Traditionally, this tool has been a physical board, with magnets, plastic chips, or sticky notes on a whiteboard to represent work items. However, in recent years, more and more project management software tools have created online Kanban boards.
A Kanban board, whether it is physical or online, is made up of different swim lanes or columns. The simplest boards have three columns: to do, in progress, and done. The columns for a software development project may consist of backlog, ready, coding, testing, approval, and done columns.
Kanban cards (like sticky notes) represent the work and each card is placed on the board in the lane that represents the status of that work. These cards communicate status at a glance. You could also use different color cards to represent different details. For example, green cards could represent a feature and orange cards could represent a task.
Kanban’s visual nature offers a unique advantage when implementing Agile. The Kanban board is easy to learn and understand, it improves flow of work, and minimizes cycle time.
The advantages of Kanban include:
- Increases flexibility: Kanban is an evolving, fluid model. There are no set phase durations and priorities are reevaluated as new information comes in.
- Reduces waste: Kanban revolves around reducing waste, ensuring that teams don’t spend time doing work that isn’t needed or doing the wrong kind of work.
- Easy to understand: The visual nature of Kanban helps to make it incredibly intuitive and easy to learn. The team doesn’t need to learn a completely new methodology, and Kanban can be easily implemented on top of other systems in place.
- Improves delivery flow: Kanban teams optimize the flow of work out to customers. Like continuous delivery (CD), Kanban focuses on the just-in-time delivery of value and delivering work to customers on a regular cadence.
- Minimizes cycle time: Cycle time is the amount of time it takes for work to move through the team’s workflow. In Kanban projects, the entire team helps to ensure the work is moving quickly and successfully through the process.
Many of the disadvantages associated with Kanban come with misuse or mishandling of the Kanban board. An outdated or overcomplicated board can lead to confusion, inaccuracies, or miscommunication.
Here’s more on the disadvantages of Kanban:
- Outdated board can lead to issues: The team must be committed to keeping the Kanban board up to date, otherwise they’ll be working off inaccurate information. And once work is completed based off an out-of-date board, it can be hard to get things back on track.
- Teams can overcomplicate the board: The Kanban board should remain clear and easy to read, however some team members may learn “new tricks” they can apply to their board. Adding these kinds of bells and whistles to the Kanban board just buries the important information.
- Lack of timing: A frequent complaint about Kanban is that you don’t know when things will be done. The columns on the Kanban board are only marked by phase (to do, in progress, complete), there are no timeframes associated with each phase, so you really don’t know how long the to do phase could last.
Every Kanban project should follow these core principles:
- Visualize the workflow: A visual representation of your work allows you to understand the big picture and see how the flow of work progresses. By making all the work visible, including blockers and queues, you can identify issues early on and improve collaboration.
- Limit work in progress (WIP): Work in progress limits (WIP limits) determine the minimum and maximum amount of work for each column on the board or for each workflow. By putting a limit on WIP, you can increase speed and flexibility, and reduce the need for prioritizing tasks.
- Manage and enhance the flow: The flow of work (the movement of work) throughout the Kanban board should be monitored and improved upon. Ideally, you want a fast, smooth flow, which shows that the team is creating value quickly. The team should analyze problems in the flow then implement changes.
- Make process policies explicit: In order for collaborative change to occur in the Kanban system, the processes need to be explicit. Everyone needs to understand how things work or what “done” really means. You can modify the board to make these processes more clear; for example, you could redesign it to specify how the work should flow.
- Continuously improve: The Kanban method encourages small, continuous changes that stick. Once the Kanban system is in place, the team will be able to identify and understand issues and suggest improvements. Teams measure their effectiveness by tracking flow, measuring cycle time, and increasing quality of work.