"And let Reform her columns roll.
With thunder peal, and lightning flash..."
- Ignis, "The Genius of Liberty" Vol III No. 2
In the past couple of articles we've seen how a Kanban board is able to help in the attainment of transparency and the stabilization of an agile team. Today we'll see if we can resolve one of the most common queries that result from this usage: how does a team decide which columns should appear on the board for tracking the progress of work items?
The simplest case...and why it may not be enough
When we set up a Kanban board in the last article, there were only three columns - or to use the correct term, "stations". These were a "Backlog" station (essentially a "To Do" list of work that has not yet been started), a station for showing which work is "In Progress", and a finally a station for representing the work that has been completed.
You can't get much simpler than that, and it begs the question as to why you would want to make it more complicated. In practice however, there are at least two situations in which this minimalist approach will be found wanting:
- A team isn't cross-trained, and its members effectively work in skill silos. Consequently we can expect dependencies between team members, some of whom may become blocked while waiting for others to complete their part of the work. The incurral of this wasted time will not be apparent if it is all considered to be "work in progress". For example, the team may be split into developers and testers, and bottlenecks may arise as work passes between them. We may need to break Work In Progress down into further stations in order to expose this waste more fully.
- Bottlenecks arise due to constraints in the workflow, which is a different problem. In this situation a team might be fully cross-trained, and none of its members become blocked waiting for another. Rather, waste arises because the work itself is inefficiently staged. This often happens with activities like development, review, and test. For example if two people are required for a review, but only one is needed for development and test, then a bottleneck may well occur. Work will build-up awaiting review due to contention for these resources and the value of the investment in effort will start to depreciate. Again the incurral of this waste will not be apparent if it is all considered to be "work in progress". More stations are needed to expose it.
Adding further stations
These then are the two key things to consider when choosing additional stations. We're out to expose waste caused by work silos, or by the inappropriate staging of activities. Either of these can introduce constraints and become the source of bottlenecks in a value stream.
Sometimes blockages can occur due to a dependency on something that must be done outside of the team. When this happens, it implies that the team are not fully in control of their own process, and consequently are unable to meet their own Definition of Done. They don't have all of the skills or resources needed. This is a problem and a contra-indication to agile practice. If it happens it's essential to make the dependency clear so that it can be challenged and removed.
We may therefore choose to have an "externally blocked" column on the board to expose problems of this nature. It isn't really a station, because it doesn't represent a state in which value is added. Rather, it shows that an item has stalled within the value stream and that the team are not in a position to provide remedy. Another option is to place a red, day-glo sticky note on the ticket highlighting the seriousness of the problem. This is a clear signal that an impediment has occurred...that is to say, in Lean-Kanban terminology, it is an andon flag. In this case the flag shows that a major blockage has arisen and needs resolving.
Challenging the boundaries
Now we need to turn our attention to the boundaries of the board. There are two principal areas we should look at. Firstly, on the leftmost side of the board, we can see the work that a team inducts into its "Backlog" prior to actioning it. Secondly, on the rightmost side, we can see the work that the team considers to be "Done".
These two boundaries are very often a source of waste. To understand why, just consider how backlogs are often allowed to grow without effective limit, and at how completed work may be permitted to accumulate in a "Done" column. These stations may not represent work in progress as far as the team is concerned, but it would be foolish to deny that they are batches too. After all, they are still part of the value stream. They represent inventory that is depreciating in value, or relevance, until something useful is done with it all. It behooves us to query the waste that is incurred, and to ask how the size of these batches may be constrained. Specifically:
- How can work be inducted into a backlog with minimal accumulation and delay?
- How can value be delivered to consumers as soon as work is completed?
- In short, what can be done to "lean" these process boundaries, so that inventory in the team's part of the value stream enters and exits in a "just-in-time" fashion?
We can answer these questions by improving transparency still further. This can mean the refinement of the "Backlog" and "Done" columns into other, more finely-grained stations. For example, work might be building up in a Product Backlog because it is not being triaged appropriately, or perhaps because acceptance criteria are insufficiently well defined. We might be able to expose these problems by replacing a backlog with "Triaged", "Accepted", and "Ready" stations. At the other side of the board, completed work may be building up in the "Done" column because a release cannot yet be made. Additional stations such as "System Integrated", "In User Acceptance", and "Awaiting Release" could add clarity here.
The simple, 3 column board we started has now exploded into a behemoth of perhaps ten columns or more. This may seem like an excessively complex structure for a workflow and a casual observer may criticize it for being fundamentally unagile. After all, inventory should either be work in progress by an agile team, or it will be awaiting their attention or have already been completed. The criticism is a valid one but we need to bear one thing in mind: these stations are there to expose problems. Only once transparency has been attained can we hope to provide remedy. The bottlenecks, along with the diagnostic stations we added to reveal them, can then be removed.
Knowing how many "columns" to include on an agile board, and what they should be, is something of a black art to many agile teams. In this article we've looked at the issues involved in making this decision. The board of a fully cross-trained team should be elegant in its simplicity, but when problems arise we must be prepared to do some digging in order to root out their causes.