Kanban is a method for managing knowledge work with an emphasis on just-in-time delivery while not overloading the team members. In this approach, the process, from definition of a task to its delivery to the customer, is displayed for participants to see and team members pull work from a queue.
The name 'Kanban' originates from Japanese[看板], and translates roughly as "signboard" or "billboard". It was formulated by David J. Anderson as an approach to incremental, evolutionary process and systems change for organizations. It uses a work-in-progress limited pull system as the core mechanism to expose system operation (or process) problems and stimulate collaboration to continuously improve the system. It is rooted in four basic principles:
Start with existing process
The Kanban method does not prescribe a specific set of roles or process steps. The Kanban method starts with existing roles and processes and stimulates continuous, incremental and evolutionary changes to the system. The Kanban method is a change management method.
Agree to pursue incremental, evolutionary change
The organization (or team) must agree that continuous, incremental and evolutionary change is the way to make system improvements and make them stick. Sweeping changes may seem more effective but have a higher failure rate due to resistance and fear in the organization. The Kanban method encourages continuous small incremental and evolutionary changes to your current system.
Respect the current process, roles, responsibilities and titles
It is likely that the organization currently has some elements that work acceptably and are worth preserving. The Kanban method seeks to drive out fear in order to facilitate future change. It attempts to eliminate initial fears by agreeing to respect current roles, responsibilities and job titles with the goal of gaining broader support.
Leadership at all levels
Acts of leadership at all levels in the organization, from individual contributors to senior management, are encouraged.
Anderson identified five core properties that had been observed in each successful implementation of the Kanban method. They were later relabeled as practices and extended with the addition of a sixth.
Visualising workflows supports proper understanding of changes planned and helps to implement them according to this plan. A common way to visualise the workflow is to use a card wall with cards and columns. The columns on the card wall represent different states or steps in the workflow.
Limit work in progress
Limiting work-in-process implies that a pull system is implemented on parts or all of the workflow. The pull system acts as one of the main stimuli for continuous, incremental and evolutionary changes to the system. The pull system can be implemented as a kanban system, a CONWIP system, a drum-buffer-rope system, or some other variant. The critical elements are that work-in-process at each state in the workflow is limited and that new work is “pulled” into the new information discovery activity when there is available capacity within the local WIP limit.
Each transition between states in the workflow is monitored, measured and reported. By actively managing the flow the continuous, incremental and evolutionary changes to the system can be evaluated to have positive or negative effects on the system.
Make policies explicit
Until the mechanism of a process is made explicit, it is often hard or impossible to hold a discussion about improving it. Without an explicit understanding of how things work and how work is actually done, any discussion of problems tends to be emotional, anecdotal and subjective. With an explicit understanding it is possible to move to a more rational, empirical, objective discussion of issues.
Implement feedback loops
Organizations that have not implemented the second level of feedback - the operations review - generally do not see process improvements beyond a localized team level.
Improve collaboratively, evolve experimentally (using models and the scientific method)
The Kanban method encourages small continuous, incremental and evolutionary changes that stick. When teams have a shared understanding of theories about work, workflow, process and risk, they are more likely to be able to build a shared comprehension of a problem and suggest improvements which can be agreed to by consensus. The Kanban method suggests using a scientific approach to implement continuous, incremental and evolutionary changes.