initial observations on kanban introduction

One of the teams I coach decided this week to adopt kanban-style limits on the WIP at each part of their value stream. It’s much too early to tell how beneficial this will prove; the transition, though, showed up a few points of interest:

  • In order to set WIP limits we had to map the company’s value stream more completely. In retrospect, the previous fuzzy understanding of the value stream had been one cause of the bottlenecks towards the customer end of the process. Kanban was the catalyst to fixing this, but otherwise unrelated.
  • Re-mapping the value stream temporarily focussed everyone on clearing some inventory, because a couple of WIP piles were initially bigger than the WIP limits we had all agreed.
  • We quickly discovered that some of the existing inventory was caused by cards only having customer value in batches. Cards had been held up in huge piles at the “Beta” and “UAT” stages, because they didn’t represent stand-alone demonstratable user value.
  • The introduction of WIP limits helped everyone to realise that the cards had been representing engineering tasks rather than customer value. So either the WIP limits had to be multiplied by the number of engineering tasks per user story, or future cards had to change and become user stories.
  • The introduction of WIP limits also served to focus everyone’s attention on the whole value stream. Previously the developers had been throwing cards “over the wall” into “Beta” and “UAT” and then forgetting about them. WIP limits quickly encouraged the developers to address bottlenecks in all areas.
  • Some of the existing value stream stages turned out to be buffers for others; and at least two of these buffers were “discovered” during the mapping exercise. We set low WIP limits on these buffers, to help squash the “over the wall” mentality.

No doubt WIP limits will throw up other subtle side-effects as the next month or so unfolds. Interesting times ahead…

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6 thoughts on “initial observations on kanban introduction

  1. @brian:

    The team initially decided to try WIP limits because the last couple of columns on their XP-style story board were bulging with cards for which no-one seemed responsible. During our early discussions about making the transition, we decided that those columns’ WIP limits should be set lower than the current number of cards there; so a cleansing exercise was called for. At that point, we began hearing conversations such as:

    “I’m sure this one has already been signed off in Beta?” — “Yeah, but it hasn’t yet been deployed to live, so we left it here.”

    It quickly became clear that there were columns missing from the story board, and so I decided that we needed to start from scratch and make sure we had a clean, clear value stream before anything else happened.

  2. Pingback: Kanban « The Art of Software Development

  3. Interesting, thanks. How much of this do you think is WIP limits and how much is simply changing the system?

    I’m wondering whether, in six months time (when the team is mature with this) another change of approach/board-layout will reveal other issues.

  4. @allan:
    The impetus for change was the recognition that there were large piles of inventory building up towards the “customer” end of the organisation’s value stream.

    The team could have decided to simply clear out the existing WIP piles, and that activity alone would have perhaps highlighted some problems with the value stream etc. But we went further: the introduction of WIP limits was an attempt to get at the /causes/ of those WIP piles and prevent them building up again.

    And this is a strong, dynamic team; in 6 months they will certainly have moved their process forward again.

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