I was reading Freddy Balle’s book The Gold Mine: A Novel of Lean Turnaround and I read something that stopped me dead in my tracks. In the book, after months of transitioning a manufacturing plant to continuous flow using Kanban, the Lean sensei asks the innocent question:

Question: What is better than Kanban?

To answer this, one must think of the purpose of a Kanban card. In manufacturing, a Kanban card is a replenishment indicator for a particular part or assembly. In software, we use Kanban to represent a piece of work such as an MMF or user story. Either way, a Kanban card represents WIP (work in process). More Kanban cards means more WIP.

What’s our goal? To increase throughput and reduce latency while minimizing operating expense. Reducing WIP is very helpful. Would be great if we could reduce our WIP as far as possible. How to do that? One-piece flow. So we reduce Kanban cards to zero.

Answer: No Kanban!

If there is no Kanban and you are very Lean, then you have single-piece flow. The holy grail of Lean process. This is what Arlo Belshee and Jim Shore attempted to explained in their LSSC10 session Enough Kanban! Use XP for Single-piece flow. (Please check it out if you haven’t seen it before.) I say attempted because I didn’t get it – I needed to read the above question and answer for the pin to drop.

So what? If you are in an environment where you can do Scrum or XP, then go do so! If not, then Kanban is great place to start. Or finish – in the case of an elite Scrum/XP team that doesn’t need iterations as training wheels.

Kanban in Context

I love Kanban – it is a great tool. One thing that I keep in mind is that Kanban is only a small part of the Lean context in which it lives. Kenji Hiranabe has a great article on InfoQ on this - Kanban Applied to Software Development: from Agile to Lean Please check out Figure 11 TPS Concept Structure: it illustrates that Kanban is just one part of the Lean system of thinking. Of course, it is a great starting place for learning it.

(Aside: I almost had a blog post without images or drawings. Then I decided I needed to do something – anything to make my point more vivid. Please excuse my primitive drawing skills.)

At Agile Coach Camp North Carolina, I had the opportunity to give a lightning talk on Kanban on my posts:

• Scrum or Kanban? YES! and
• Kanban is a Gateway Drug

Here it is:

You may wish to check out the other lightning talks.

For years I have preferred Scrum as a starting place rather than XP since it is easier to adopt. One of the patterns of Fearless Change is to take small steps. Scrum is a much smaller step than XP. That’s old news. Lot’s of folks like to start with XP, that’s OK by me.

Probably a good thing to clarify at the start is that Kanban is part of the Agile family of processes.

Kanban is easier to adopt than Scrum

Way easier. Like almost trivial. Let’s see: no process change, no role change, no change in team structure. Just make the work visible. Wow! There is so much value in just making the work visible. Lot’s of little problems can be fixed and voila – productivity and cycle time gains.

Kanban uses Kaizen = Continuous Improvement

Kaizen is about continuous improvement. Define a standard process and then start improving. Take smalls steps. Get everyone involved. Kanban is a standardized process flow that starts with the existing process.

In the graph of performance vs time on the left, kaizen will result in improvements that will asymptotically approach the limit within that paradigm.

As teams mature, they may go beyond this into the place where Scrum/XP start…

Scrum/XP is Kaikaku = Radical Overhaul

Kaikaku is discontinuous improvement. It is about a revolution in the way things are done. It is also called Breakthrough Kaizen.

Can anyone say Scrum or eXtreme Programming? It changes work groups, job titles, roles, and project basics. For contexts where Scrum is a good fit, it is a high-value, high-cost game-changing move. James Shore has a great post on Kaizen and Kaikaku where he argues that this is a better starting place if you want a high-performance team.

What does this look like in terms of performance? See graph below. It looks like Virginia Satir’s Change Model.

In the Lean world, companies use both kaizen and kaikaku depending on circumstances as they are complementary approaches.

Why a gateway drug?

The gateway drug theory states that softer drugs (Kanban) can lead to harder drugs (Scrum, XP). This is a great metaphor because this theory has been proven as well as dis-proven. To quote David Anderson “we are only beginning to understand the differences between Scrum and Kanban”.

Do I believe in the the theory? I’m not sure that I care – as long as people are working to improve their work environments at a pace that works for them, that is good enough for me. For me, any Agile is good –  it does not need to be one particular style.

Let’s face it – lot’s of organizations are ready for a radical overhaul. For companies like these, Kanban is a great place to start. Getting off the sofa and going for a marathon may not be a good idea. For some it may be better to start by jogging around the block.

Other Perspectives

David Anderson has a contemporaneous post (go read it, it’s good) supporting the notion that Kanban is primarily focussed on continuous evolution until the organization has enough maturity for more radical changes.

Ken Schwaber is continuing the drum beat that Scrum is the one true path.