In the 1940’s, Toyota discovered that their production process could be improved by implementing a visual system for monitoring the flow of parts from the supplier, to the warehouse, and to the assembly line. The system of matching inventory with demand allowed for a “just-in-time” provisioning and production process that reduced costs, improved quality and sped the pace of production.
They called the process Kanban, which is the Japanese term for “signboard” or “visual signal.” The approach was effective and “Kanban Cards” began appearing in manufacturing companies across the globe.
Many workers today are engaged in work that does not involve a physical production line, but notable business thought leaders, many influenced by the work of David J. Anderson and Jim Benson, realized that the core principles of Kanban can be effectively leveraged by knowledge workers to gain the same quality and efficiency improvements enjoyed by manufacturers.
For example, a software development process can be imagined as a figurative assembly line with feature requests starting one end and improved software coming off the line on the other end. Visually tracking the movement of the work from beginning to end helps identify and prevent bottlenecks and ensure that all work in progress is completed in the expected time frame.
The four principles of Kanban apply equally well to knowledge and factory work. They are:
Kanban starts with the creation of a visual model of work and workflow. This allows all stakeholders to observe the flow of work. The progress of work, including the blockers, bottlenecks and queues, is made clear for all to see, thus improving communication and results.
The visualization can be as simple as Post-it-notes on a white board, or it can be created digitally. Here is an example of a simple Kanban board for a development team.
Limit Work in Progress (WIP)
In line with the “just-in-time” goal, work moves from one stage to the next only when pulled through by “customer” demand (or the next downstream stage in the process). The amount of work in the pipeline is always limited to what can be managed within a given time frame. For example, developers would not complete more enhancements than the quality assurance team has the capacity to test.
Focus on Flow
When workflow is visualized and work in progress is limited, work flows freely from start to finish. Any interruption in flow can be identified and resolved before a backlog begins to form. This is important because work sitting in the pipeline ties up investment, increases distance to customer value, and creates prioritization conflicts.
In the example above, the number under each group represents the number of items that team can reasonably address in a given week. Item number 5 is "blocked" because it has been completed before the quality assurance team can pull it into work in progress. The supervisor can easily recognize this problem and take the necessary steps to resolve it before the backlog grows.
The Kanban approach requires constant monitoring and analysis to look for opportunities for improvement. Team effectiveness can be measured by tracking flow, throughput, production pace and quality.
Visualization is a powerful tool for improving processes in any type of business. Limiting WIP is an important strategy for people who try to "bite off more than they can chew" in a workday.
While it is simple, the Kanban approach helps teams operate more efficiently, reduce friction and maintain a smooth flow of value to customers. It is an inexpensive and low risk option for organizations focused on continuous improvement.