What is Kanban?

Kanban is a popular framework used to implement agile software development. It requires real-time communication of capacity and full transparency of work. Work items are represented visually on a kanban board, allowing team members to see the state of every piece of work at any time.
Kanban is a scheduling system for lean manufacturing and just-in-time manufacturing . Taiichi Ohno, an industrial engineer at Toyota, developed kanban to improve manufacturing efficiency. Kanban is one method to achieve JIT. The system takes its name from the cards that track production within a factory. For many in the automotive sector, kanban is known as the “Toyota nameplate system” and as such the term is not used by some other automakers.

Kanban became an effective tool to support running a production system as a whole, and an excellent way to promote improvement. Problem areas are highlighted by measuring lead time and cycle time of the full process and process steps. One of the main benefits of kanban is to establish an upper limit to work in process inventory to avoid overcapacity. Other systems with similar effect are for example CONWIP.

A goal of the kanban system is to limit the buildup of excess inventory at any point in production. Limits on the number of items waiting at supply points are established and then reduced as inefficiencies are identified and removed. Whenever a limit is exceeded, this points to an inefficiency that should be addressed.

Kanban is based on 3 basic principles:

1) Visualize what you do today (workflow): seeing all the items in context of each other can be very informative
2) Limit the amount of work in progress (WIP): this helps balance the flow-based approach so teams don€™t start and commit to too much work at once
3) Enhance flow: when something is finished, the next highest thing from the backlog is pulled into play

Types of kanban systems
In a kanban system, adjacent upstream and downstream workstations communicate with each other through their cards, where each container has a kanban associated with it. Economic Order Quantity is important. The most important types of kanbans are:

1. Express kan-ban – used when shortages of parts occur

2. Emergency kan-ban – used to replace defective parts and other uncertainties such as machine failures or changes in production volumes

3. Through kan-ban – used when adjacent work centers are located close to each other. It combines production and withdrawal kan-bans for both stages onto one, through, kan-ban

4. Production (P) Kanban: A P-kanban, when received, authorizes the workstation to produce a fixed amount of products. The P-kanban is carried on the containers that are associated with it.

5. Transportation (T) Kanban: A T-kanban authorizes the transportation of the full container to the downstream workstation. The T-kanban is also carried on the containers that are associated with the transportation to move through the loop again.

The benefits of Kanban
Kanban is one of the most popular software development methodologies adopted by agile teams today. Kanban offers several additional advantages to task planning and throughput for teams of all sizes.

1) Planning flexibility
A kanban team is only focused on the work that’s actively in progress. Once the team completes a work item, they pluck the next work item off the top of the backlog. The product owner is free to reprioritize work in the backlog without disrupting the team, because any changes outside the current work items don’t impact the team. As long as the product owner keeps the most important work items on top of the backlog, the development team is assured they are delivering maximum value back to the business. So there’s no need for the fixed-length iterations you find in scrum.

2) Shortened time cycles
Cycle time is a key metric for kanban teams. Cycle time is the amount of time it takes for a unit of work to travel through the team’s workflow–from the moment work starts to the moment it ships. By optimizing cycle time, the team can confidently forecast the delivery of future work.

Overlapping skill sets lead to smaller cycle times. When only one person holds a skill set, that person becomes a bottleneck in the workflow. So teams employ basic best practices like code review and mentoring help to spread knowledge. Shared skills mean that team members can take on heterogeneous work, which further optimizes cycle time. It also means that if there is a backup of work, the entire team can swarm on it to get the process flowing smoothly again. For instance, testing isn’t only done by QA engineers. Developers pitch in, too.

In a kanban framework, it’s the entire team’s responsibility to ensure work is moving smoothly through the process.

3) Fewer bottlenecks
Multitasking kills efficiency. The more work items in flight at any given time, the more context switching, which hinders their path to completion. That’s why a key tenant of kanban is to limit the amount of work in progress (WIP). Work-in-progress limits highlight bottlenecks and backups in the team’s process due to lack of focus, people, or skill sets.

That might seem like a low limit, but there’s good reason for it: developers often prefer to write new code, rather than spend time reviewing someone else’s work. A low limit encourages the team to pay special attention to issues in the review state, and to review others work before raising their own code reviews. This ultimately reduces the overall cycle time.

4) Visual metrics
One of the core values is a strong focus on continually improving team efficiency and effectiveness with every iteration of work. Charts provide a visual mechanism for teams to ensure they’re continuing to improve. When the team can see data, it’s easier to spot bottlenecks in the process (and remove them). Two common reports kanban teams use are control charts and cumulative flow diagrams.

A control chart shows the cycle time for each issue as well as a rolling average for the team.

5) Continuous Delivery
We know that continuous integration–the practice of automatically building and testing code incrementally throughout the day–is essential for maintaining quality. Now it’s time to meet continuous delivery (CD). CD is the practice of releasing work to customers frequently–even daily or hourly. Kanban and CD beautifully complement each other because both techniques focus on the just-in-time (and one-at-a-time) delivery of value.

The faster a team can deliver innovation to market, the more competitive their product will be in the marketplace. And kanban teams focus on exactly that: optimizing the flow of work out to customers.

Values
Teams applying Kanban to improve the services they deliver embrace the following values:

Transparency – sharing information openly using clear and straightforward language improves the flow of business value.

Balance – different aspects, viewpoints, and capabilities must be balanced in order to achieve effectiveness.

Collaboration – Kanban was created to improve the way people work together.

Customer Focus – Kanban systems aim to optimize the flow of value to customers that are external from the system but may be internal or external to the organization in which the system exists.

Flow – Work is a continuous or episodic flow of value.

Leadership – Leadership (the ability to inspire others to act via example, words, and reflection) is needed at all levels in order to realize continuous improvement and deliver value.

Understanding – Individual and organizational self-knowledge of the starting point is necessary to move forward and improve.

Agreement – Everyone involved with a system are committed to improvement and agree to jointly move toward goals while respecting and accommodating differences of opinion and approach.

Respect – Value, understand, and show consideration for people.