Part 1 of 2: Kanban vs Scrum Myths and Hype
Recently, I heard folks at a few of my clients and at a couple conferences talking about why they are considering moving to using Kanban vs. Scrum. I have no preference to either method other than choosing the right agile development tool for the job. My concern derived from what I have heard identifies the beginnings of some myths and also demonstrates some of the hype around Kanban.
First, a clarification; Kanban with a capital (K) is the term David Anderson coined with respect to an agile development approach to driving change based on lean principles. Kanban with a little (k) represents the idea of the “sign” or “billboard” that provides the signal/visibility in a production line for additional demand for service of a particular station. It is one of the tools that enables just-in-time (JIT) action as described in the Toyota Production System.
Kanban, as Anderson explains in his book, relies on change occurring in more of an optimizing manner (see kaizen culture).
This is the significant difference between Kanban and Scrum. In a Kanban approach, an organization can begin with their current practices with a few exceptions. Kanban requires:
- A high degree of visibility into the state of all work queued and in progress
- Absolute respect for WIP limits
- A commitment to execution in a ‘pull-based’ manner from the prioritized work queue
Kanban also demands a focus on quality. In fact, this is Anderson’s first step in his six-step recipe for Kanban. Quality comes first primarily because of the obvious cause-and-effect relationship to waste — and because it’s generally more in the direct control of technical management. Working down his recipe, there tends to be less control and influence over the changes by technical management.
Now for the Myths and Hype
Myth: Scrum has work pushed onto the team while in Kanban work is pulled into the system. This is incorrect. Scrum does not have work “pushed through the system.” It is a pull-based agile development system with work pulled in larger batches (the Sprint Backlog). A Scrum implementation (as well as Kanban) becomes a ‘push-based’ system when the business doesn’t respect the current proven capability of its teams to produce value and just continues to push demands for service into the system.
Hype: Kanban at its core is summarized by the premise: ‘Stop Starting, Start Finishing’. The entire team’s focus is on ‘getting to done’ for the tasks in progress. This statement is certainly true of Kanban, but the implication that Scrum does not have this focus is not true. Scrum done right has the same focus, delivering software sooner and doing so in priority order to maximize the value delivered to the customer. I’ve coached to Scrum teams for years that, wherever possible, everyone on the team should work on the highest priority item and get it done first before starting on the next item in the Sprint Backlog. This implies limiting WIP, as well as focusing on delivering the Backlog in rank order.
If the focus of a Scrum team is to just get everything in a Sprint Backlog into an in-progress state, regardless of priority, then you have a dysfunctional team that’s most likely not working cross-functionally and certainly not focused on delivering the highest-value items first.
Hype: The statement, “The Kanban method is intuitive and is quickly and easily adopted by teams,” to me is a statement that’s used irresponsibly. It is too often a battle cry of those trying to sell Kanban as a product. It is the cop-out reason used by many organizations who are failing at Scrum and looking at Kanban.
In Part 2 of this post we’ll continue the conversation about implementing Kanban and some of fundamentals that hold back Kanban and Scrum implementations.