When it first appeared, Agile was largely a developer-driven initiative. As a result, many teams optimized only a part of the software product's "value stream." Once development got sorted out, many teams discovered they'd sub-optimized, i.e. improved development but still hamstrung by constraints outside their control. Lean emphasizes optimization of key bottlenecks wherever they happen in the value-stream - for software, this could be anywhere between the initial request for a solution and the final delivered solution in the hands of the customer. In this InfoQ article, Kanban Applied to software development: from Agile to Lean, Kenji Hiranabe explores the history of Lean manufacturing's "Kanban" visual tracking tool, and how it differs from the commonly-seen Agile taskboard. He proposes that by moving from our Agile tracking systems to the Lean Kanban approach, we can see more far-reaching improvements happen across the organisation.
Hiranabe suggests that teams can use Kanban to increase visibility beyond the teamroom, to encourage real improvement throughout the value-stream. His solutions include Agile Kanban for research-oriented teams with little repetition in their work, and Sustaining Kanban for production-support work, where tasks are more predictable and repeatitious.
The article includes a detailed analysis of the properties of Kanban, and explains how it fits into a process as a tool for Kaizen and to control Work-in-Progress:
- Physical: It is a physical card. It can be held in the hand, moved, and put into or onto something.
- Limits WIP: It limits WIP (Work-In-Process), i.e. prevents overproduction.
- Continuous Flow: It notifies needs of production before the store runs out of stock.
- Pull: The downstream process pulls items from the upstream process.
- Self-Directing: It has all information on what to do and makes production autonomous in a non-centralized manner and without micro-management.
- Visual: It is stacked or posted to show the current status and progress, visually.
- Signal: Its visual status signals the next withdrawal or production actions.
- Kaizen: Visual process flow informs and stimulates Kaizen.
- Attached: It is attached to and moves with physical parts supplied.
The article concludes with an overview of the Toyota Production System. While most software development is quite different from manufacturing, it's this model, adapted for software, which inspires the Lean Software Development movement.
Read the InfoQ exclusive article Kanban Applied to software development: from Agile to Lean, by Kenji Hiranabe.