Teams assigned to Lean-Agile for the first time bring with them the habits of traditional approaches to courseware project management. The Lean-Agile Coach had to remind teams and Leads to use pull tasks rather than assigning (push) work as the rule, then doing any exceptions. It was different from prior experience and for some took longer to abandon than others.
This next point is repeated from earlier because it is important in shifting to the Lean-Agile mindset. New teams would have someone pull 15 or 20 work item cards into their work in process column on the Kanban board. At the next daily synchronization meeting, the coach would ask why. "Those are the things I have to work on" would come the reply.
Then, the Lean-Agile Coach would explain that the metrics behind the scenes with the virtual Kanban board is measuring hands-on time versus waiting-in-a-queue time. Hardware maintenance people sometimes call this "wrench time" versus other. We would explain that we want 13-14 cards to stay in the ready queue just prior to the WIP column and for the person to pull only 1-2 cards into the WIP column.
Some would voice agreement but take a few days to get it right. Others got it faster.
Traditional process steps might look like this:
Process Step X
Process Step Y
The person working process step X finishes his work items and pushes them to process step Y. If the person in process step Y cannot keep up then a bottleneck builds.
In Agile, most process stations, columns on the Kanban board, in the process flow include at least two columns:
Ready queue (typically the prior process step A "done" column)
Process Step B WIP column
Process Step B "done" column
Process Step C WIP column
Process Step C "done" column
The person finishing step B moves their work item card as they complete each into their own Step B "done" column and pull another card from step A "done" column which is their ready queue. This is like the stop light on the LA freeway on-ramp. The person working Process Step C, pulls only 1-2 cards at a time as they have open capacity from Step B "done" column. They work each card and move it to the Step C "done" column.
Kanban applies Goldratt’s Theory of Constraints. The summary of this theory is:
The whole system performs only as well as its bottleneck.
Ensure you have slack before and after the bottleneck. This happens automatically with pull scheduling.
Use the slack to fix the bottleneck.
Pull prevents bottlenecks.
A queue distinguishes work that is eligible to be pulled from work that is still in process. Queues start backing up immediately following any blockage.
When someone needs another task to perform, they pull the top item from their ready queue or the backlog because that is the highest priority work item.
Daily synchronization meetings with the team traverse the Kanban board from right to left to emphasize pull.
Pull is work processing actually triggered by downstream customer demand rather than a forecasted schedule, and Kanban signals visually trigger this demand to flow through the value stream. As the Kanban columns/process steps empty out, team members have a visual signal to pull another work item card from the prioritized backlog. Kanban column WIP limits indicate the maximum capacity for that process step and the maximum work items the team member should pull into this column. Although you may see the Lean manufacturing roots in this definition, it applies equally well to knowledge work, so we use it.