There is a lot of discussion going on in the net right now on the issue of single piece flow as a great tool for ... actually what? This is actually rarely defined. (And I think that is the issue of a lot of misunderstanding and disagreeing on things that are actually agreed upon - context being left out.) Also it is brought into play as a true north for a continuous improvement process - as the means of all means, the end of all ends which will lead to the ultimate goasl - the dissolving of the Kanban. Hmmm. I doubt it. Before we go further let's have a look into the follwing recruitment ad:
Looking for Software Developers
Nickel & Dime Inc. is a new software shop that is working on highest qualty standards. We have opened new facilities that are working under lowest WiP limits. We have achieved a great level of flow. We now want to go to the next level and we are seeking your support: we want to achieve sustainable single piece flow throughout our software shop. If you are not only up for the adventure of getting there but also working under a strict, sustained single piece flow for the next years, no matter what product will be developed, no matter what other factors are weighing in - you are our man. Call us under 0800-111111
This is an impression for the recruitment going on for a company going for single piece flow in software development. Are you likely to hire? Are you likely to stay? Why? Why not?
Let's say Nickel & dime really hasn't achieved 1x1 flow yet. To get there immedeately means revolutionary change. Which problem would be triggering the need for 1x1 flow and solved right away that would justify revolutionary change?
OK, let's not go for revolutionary change but instead use Kanban to control WIP. We lower WIP piece by piece, make problems in the flow visible, caused by whatever issues in handover and development process and environment. We resolve those issues. At least we now have an idea which problems we are facing when we opt for revlutionary change. Let's say all goes well. We achieve 1x1 flow after a certain time. Did we have the right true north now, leading us through the continuous improvement w/ Kanban? That would mean we are in Nirvana now, happy, happy for ever? To answer that question, look at the recruitment ad again. Do we want to develop in strict 1x1 flow for the rest of our time? I guess not. If not, why did we go there, why did we choose that exact true north of 1x1 flow?
Then, why did Toyota choose 1x1 flow as true north? Because in manufacturing, where you want to elminate variability this makes sense. You want to have a great takt time. As Jim Benson of Personal Kanban fame, @ourfounder tweeted today,
"1 pc flow is based on perfect value stream and like sized / defined work items. Knowledge work has high vriation of work items, rapidly changing contexts and fast evolution. Therefore 1 pc flow achieved will either be temporary or for subsets of the overall work. The moment 1 piece flow is achieved for an entire prod dev process, it ceases to be knowledge work."
This is completely different at Toyota. They go for a minimum of variation, which is the complexity they have to master. Therefore, getting ever closer to 1x1 is the right challenge and the right true north. Still, they use it as an Utopia, no place nowhere and in fact they will never reach it across the whole line. Even less will they reach the even more favorable true north of 1x1 flow in the sequence of incoming client orders. They still try to - all of the time. They'd even be happy to get there. Except for one reason. This is where the Toyota Kata comes into play, which is embeded into their change, indeed defines their change all over the place. They are seeking for ever new small, but challenging steps getting closer to 1x1. The only reason being to make new production problems visible and trying to resolve them. The reason behind that is simply and at the same time as a stroke of genius to keep moving and in a problem solving mode all the time. What is happening along the line is that Toyota keeps awake and energized and creative all the time. Highest quality, great products, etc. are all great but calculated side effects.
So, if we in our industry take 1x1 as the true north, would we get the same benefits as Toyota? As we are talking about knowledge work and everything Jim mentioned in his few sentences, aren't we rather risking customer focus and generation of value? I have been fiddling with the idea of 1x1 flow for a long time now - because it seems attractive, elegant, compelling. When I think it to the end - for myself - I come to the conclusion that this leads to inward bound, process releated activity rather than customer facing benefits. It gets a stale, dead end best practice with no added value.
I do see a value in 1x1 flow, though, which is using it for a sgort perod of time as a didactical tool to show teams definciencies in flow, excessive handovers, immature PD processes and environments. It is a tremendous learning experience in our field - for a certain time. No more, no less. WhenI talk about 1x1 flow I will make sure that this is the purpose I see in it.
Kanban done right will actually help to achieve Rightflow, the right level of WIP under the given context.
What do you think?