Sunday, June 23, 2013

KANBAN in s/w development (2)

KANBAN in s/w development is quite different from Kanban in production. Although both are visual planning systems using cards, there are significant differences as well.

Carefully watch the flow. The Kanban in production is clearly pull. And while it is being mentioned in the video that KANBAN in s/w development is pull, it is clearly a do-not-over-push!

Kanban in production

KANBAN in s/w development

There are a couple more differences as well.

Kanban in production, due to the need to be able to react on unpredictable demand, requires the available capacity to be larger than the demanded capacity. E.g. people and machines must be idle for tome time from time to time.

In production it is exactly known what must be done in each step; both the exact predefined outcome as what steps to follow to create that result. Any worker with the proper training can step in half way the work on a workstation and pick up the work directly without giving it much thought. Standardization, routine, more of the same are key.

Both the idleness and standardization, two requirements for Kanban to work in production, are not present in software development.

The do-not-overpush mechanism is not present in Kanban for production. It is not needed for the card mechanism in production makes it impossible to ask for more products than there the number of cards available. The number of cards is limited by design of the system.

There is one requirement that is essential in s/w development to work and is usually not touched: use cases must be independent.

Short itteration cylces usually reduce the existance of dependency between use cases within and even between a few itteration cycles. However when an itteration cycle is 'long' dependencies will pop-up and will reduce the workability of KANBAN for ICT as it is now.

Even with short itteration cycles, one must be prepared to 'throw way' or 'redo' certain use cases due to additional, new or changes in use cases. This form of waste is a necessity stemming from the reluctance to look 'further' in the future.

For good reasons by the way. Usually the waste coming from short time horizon thinking is little to nothing compared to the wast stemming from large or even medium time horizon thinking.

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