Incremental Software Development without Iterations
David Anderson described how his team is using a kanban system for their sustaining engineering (maintenance and bug fixing) activities. Iterations have been dropped although software is still released every two weeks. Work is scheduled, monitored, and run via a "kanban board" and daily stand-up meetings.
Kanban comes directly from the Toyota Production System and Lean Manufacturing and is an Information Radiator that is used as the touch point for a team to coordinate tasks through production. This is an idea that is not new to Agile - although obviously it did not originate from our community. What Anderson and his team have done is an excellent example of applying ideas of Lean Production principles to remove, previously necessary, waste from the system. Do we really need the planning, estimation, and other overhead for Iterations when in the maintenance releases?
It uses a kanban system to pipeline change requests (CRs). When a CR is complete it sits in the Release Ready state until a scheduled release happens on every second Wednesday.
This approach also removed one common constraint with Iterative development, that all problems have to be broken down to fit into one Iteration:
The kanban system also frees us from the constraints of time-boxed iterations. Even though we are making a release every two weeks, items in the system can take up to 60 days to move through depending on their size and complexity. Items that would be too big for a single two week iteration can still be fed in to the system and will work through and be released without any special management attention.
Those are the positive aspects of this method. However, is this a technique that is responsive to change? There are no synchronizing points such as demos and retrospectives to provide feedback about the process itself. That said, Anderson's team has already diagnosed one problem related to team members working remotely:
Well it turns out that keep them in sync is problematic especially when people are working from home or otherwise remotely. Darren Davis has instituted a "sticky buddy" scheme where people who are WFH for the day, have to designate a in-office buddy who will update the white board for them and keep it in sync with the electronic tracking system.
So it seems their team is able to obtain feedback using the daily stand-up meeting. Will this continue to be enough?
I have also seen teams discuss doing this when they feel pain from Iterations. Instead of solving their problems with Iterations, they want to avoid them. (The same reasoning that goes behind integration at the very end of a release.)
Managing Release-Spanning Features
Ultimately, I'm not convinced this approach offers a significant benefit over iterations, although I'm not against it. I'm inclined to believe that a staged pipeline like this works well in some environments, although I've mostly considered using this in gathering requirements rather than implementing software.
Kanban limits WIP