In the introductory Kanban post, I provided some background on Kanban in order to give you some context for how Kanban might be used in an agile software development environment. Now I want to provide some insight on how Kanban is currently being used with agile and why I think the idea of doing so holds some merit.
In Part 1, I mentioned that Kanban and Agile share some basic tenets: improve efficiencies in a non-prescriptive environment where rules are kept to a minimum. I also said that at the very least, incorporating Kanban into an agile environment by combining rules 5 and 6 of Toyota’s Production System (TPS) seemed to make the most sense. In other words, using Kanban as a means for fine tuning in order to stabilize and rationalize the process could bring a lot to the table in an agile software environment.
Let’s take a look at some of the ways it’s been done so far.
In his article, Kanban Applied to Software Development: from Agile to Lean, Kenji Hiranabe discusses several ways Agile and Kanban have been put into practice, including:
Hiranbe equates Agile Kanban to ‘Task Kanban’ in that, like Agile, it doesn’t show processes, such as Development, Testing and Deployment, but instead relies only on visual cues that show the status of a story, such as To Do, Doing and Done. He uses this photo of a Task Kanban implemented by the JUDE development team at Change Vision, Inc. to illustrate:
Unlike Agile or Task Kanban, Sustaining Kanban has separate and serial processes (Development, Testing, etc.) and the Kanban cards move between those processes from left to right, as shown in this example, a pieced-together image of Yahoo’s Kanban system from Jeff Patton in his article, Kanban Development Oversimplified.
How Yahoo’s Kanban board works:
Although at first glance you might think otherwise, Hiranbe explains, “Sustaining Kanban is not a classic waterfall process, where all the requirements are ‘designed’ at one time, ‘developed’, and ‘validated’ at another time, which would cause all the cards to move in a group. Instead, the cards move one by one, like the one-piece-flow of manufacturing.”
Using the Yahoo example, you can clearly see the “flow of work” concept used in Sustaining Kanban is different from the “iteration” concept of agile. And, in order to be a true ‘pull’ system, rules would need to require that only the next group to the right is allowed to move the cards on the board.
Hiranbe describes Lean+Agile Kanban like using Agile Kanban synchronously within each process and using Sustaining Kanban asynchronously across the whole value stream of processes
Patton also found a smaller “portable” Kanban system he in a project being developed by Central Computer Services, Co. At Central, a team works in several smaller sub teams (usually pairs). When a sub-team pulls a user story, they break it down into their tasks and post them onto their own portable Kanban board (in this case, a bulletin board they can carry with them).
In Central’s case, the Kanban system consists of two levels:
Central uses the term ‘Kanban-nano’ to refer to its agile-Kanban system.
The idea of using a simple task board with index cards or sticky notes is as old as Agile itself.
Even after seeing only a few styles of Kanban in place for agile software development, it’s certainly not a stretch to imagine other variations that could be used in order to create hybrid agile-Kanban systems. One example is Scrumban, fully discussed by Corey Ladas in his 2008 paper, in which he describes Scrumban as “Incrementally enhancing Scrum with more and more pull-like features.” In doing so, Ladas says, flow becomes smoother as process capability improves, providing opportunities for kaizen.
The beauty of the Kanban system: it’s very visual. If logjams occur they’re obvious and action can be taken to address them.
Over time, the process of improving the system is considered ‘smoothing’ or production leveling, and is sometimes referred to in production as “heijunka”. It’s a technique for reducing waste and is an important part of the production efficiency in the TPS and in lean manufacturing in general.
So, at least to this point, you might agree as I said in part 1:
“At the very least, incorporating Kanban into an Agile environment by combining rules 5 and 6 of the TPS seems to make a lot of sense, i.e., using Kanban is a means to fine tuning in order to stabilize and rationalize the process.”
Phew, that’s enough to read for now. In Part 3, I’ll discuss some of the tradeoffs that might occur and if bringing Kanban into an agile environment necessarily means we lose the collaboration between teams with different perspectives, a very important part of product development in my mind.
I’ll also provide some additional resources you can use to find more information on using Kanban in an agile environment.
I’ve never made it a secret that I am a fan of agile management practices, both inside and outside of software development. Historically, however, two things within the agile space have always been a little bit frustrating to me:
I have heard about Kanban systems applied to software development for a while now, but mostly through conversations with other agile practitioners. After doing some research, I’ve found that there were not many resources on the internet about Kanban and how it is used in agile development. So I decided to pull something together here and use it as a basis for further discussion.
First, what exactly is Kanban?
The word kanban is Japanese. Roughly translated, it means ‘signboard’, ‘billboard’ or ‘card you can see.’ In its original usage in 17th century Japan, Kanban was a wooden or metal sign often used to represent a trademark or seal.
In more modern times, however, Kanban became a term used in Just-in-time (JIT) manufacturing systems that seek to reduce in-process inventory and its associated carrying costs, most notably by Toyota. Thus the concept of Just-in-time manufacturing has also become known as the Toyota Production System (TPS).
JIT or TPS is a lean, pull system of production. American manufacturing has traditionally been based on a push system where the manufacturer estimates the quantity of product it must produce in order to meet forecast demand. A push system can result in either a shortage or surplus of materials needed for production depending on the accuracy of that forecast.
Conversely, pull systems like those used in the TPS rely on observed and not forecast demand. Signals at different points in the process are used to determine when more parts are needed. To illustrate the concept simply, imagine a parts bin on the factory floor with a Kanban card (signal) inside that carries part identification. When the bin is empty, the bin and the card are taken to the factory’s store for replacement. The factory store replaces the empty bin with a full one containing its own Kanban card. The factory store then presents the empty bin and its Kanban card to the appropriate step in the supply chain for replenishment.
In such a system, as long as there is one spare in the factory store, the process will never run out of needed parts and supply costs are only incurred when they’re actually necessary. While it may not seem revolutionary at first blush, it turns out that it is. This subtle shift in thinking can have a dramatic impact on efficiency and waste.
The general flow of Kanban would look something like this:
By now, you’re probably thinking:
“This is all well and good in a factory production line, which is a very linear process where the product moves from one assembly stage to another in orderly fashion and once the product moves form point A to point B, it doesn’t come back (provided quality is satisfactory when it arrives at point B). But software development doesn’t always operate in a linear process.”
It’s true that flow is often non-linear with software development. It’s not always a clean handoff from elaboration to development to testing. Sometimes design and development are happening in parallel, for example. Plus, we’re talking about labor and not physical, raw materials.
However, Kanban is in use in lean non-manufacturing environments and, in fact, Kanban has already been adopted in some agile software development environments. That’s likely because Kanban is relatively easy to adapt to specific environments because there aren’t a lot of rules.
Kenji Hiranabe1 succinctly lists the rules of Kanban as:
And, in fact, Toyota’s TPS itself has only six very simple rules:1.
In non-manufacturing environments, the primary purpose of Kanban is to facilitate efficient workflow. In manufacturing it’s about having the right part in the right quantity at the right time. This is as opposed to producing based on guesswork and estimation. It’s about being lean. Very lean.
The real question then, is “Does Kanban conflict with Agile concepts/principles?”
The best answer might be, “In some ways, maybe. In some ways, maybe not.”
Over the last several years a large number of Agile practitioners have begun to include thinking from lean manufacturing in their Agile approaches, thanks to trailblazers like Tom & Mary Poppendiek in their book Lean Software Development. But Kanban, at least as discussed thus far, seems to break the primary rule of today’s common agile practice: the fixed development time-box. Kanban systems are continuous, not iterative, yet both exist to promote workflow efficiency.
In his article, Kanban Development Oversimplified, Jeff Patton illustrates some of the conflicts between Agile and Kanban. With Kanban development:
Implementing Kanban in an Agile environment might require a bit of ‘shoehorning’ to make it work. But Kanban and Agile share some basic tenets: improve efficiencies in a non-prescriptive environment where rules are kept to a minimum. In this way, they certainly seem complementary.
At the very least, incorporating Kanban into an Agile environment by combining rules 5 and 6 of the TPS seems to make a lot of sense, i.e., using Kanban is a means to fine tuning in order to stabilize and rationalize the process. And, just as Agile has evolved into several different flavors over time, like XP and Scrum, it’s not a stretch to imagine Agile-Kanban hybrids like Scrum-ban just might create a synergy for software development that neither could achieve on its own.
I’ve laid the groundwork by providing some context on the possibility of using Kanban in an Agile software development environment. Just as I think different forms of Agile shouldn’t be seen as conflicting but as complementary, I also think it’s important to keep an open mind and consider that Kanban and Agile have the potential to be complementary and not contradictory. The subtle shift in lean thinking turned out to be revolutionary in classical production, and it may just have a significant impact in the world of agile as well.
In Part 2 I’ll take a look at how Kanban is currently being adopted in Agile environments and the key tradeoffs that might result.
Effectively managing conflict in the workplace has been a topic on my mind for some time now. Having a new topic on your mind is kind of like buying a new car; you start to notice it everywhere. Now that I am thinking about effectively managing conflict, I am starting to see conflict or opportunities for healthy conflict everywhere. One of the most challenging things for one to think through as they try to create a healthy conflict culture is figuring out exactly what is worth ‘fighting over’ and what isn’t.
One has to be careful not to let the pendulum swing too far in the other direction, and turn everything into a ‘fighting moment.’ It’s very easy to get ‘caught up’ in disagreements about all sorts of details that aren’t worth the time. That’s not the kind of culture anyone wants to create. Healthy conflict has to be effectively separated from petty conflict.
So far, based on my reading and studying of the subject, there are three tests that a topic can pass to be worth engaging in healthy debate and conflict over:
The second bullet is perhaps the hardest one to figure out. I think that Dr. Saj-nicole Joni describes the concept pretty well in her book titled “The Third Opinion.” She describes three types of thinking:
The key to finding the right problems lays in exponential thinking. The first two types of problems are typically too simple to try and bring multiple perspectives to the table on. Also, there is likely to be one right answer that is simply a matter of knowledge or expertise.
The key takeaway for me here is that conflict takes energy and time. For most of us (especially me) it has a sapping effect. I don’t necessarily love conflict, and I suspect that I am not alone. So it’s important to find the right balance of it, and it’s even more important to do it for the right reasons. While no acid test is perfect, the one above has been pretty effective for me so far!