Originally published February 21, 2016
I have been searching for a temporary work visualization method to adequately convey both how a given process works and the WIP (Work In Progress) within it at any given moment. With eventual improvement set as a goal for the former, a prerequisite for any productive discussion is a common understanding from which to work. For the latter, understanding WIP prevents us from making a bad process worse and allows us to free up capacity to improve.
Kanban seemed like something to try, but I realized I was considering only the information Kanban provides and not the functional purpose it is intended to fulfill.
More specifically, an organization addicted to pushing work through the system will probably fail to adequately control the release of work, allowing for further inventory buildup between steps. Only simplistic bottlenecks on individual steps will be apparent, and representation of a nonlinear flow in terms of system constraints isn’t accounted for (i.e., one particular step performed at one particular station precludes the ability of a different step at that same station to be performed).
I considered a value stream map next, but the detail of a fully-formed VSM would only serve as a barrier to common understanding and is not meant to represent WIP. Hence, consideration of a stateful, simplified form:
This visualization steals a bit from Critical Chain concepts by acknowledging the utilization and occupation of individual resources, conveying circumstances where a resource (or a person) might be busy with another step of the process, such as with Workstation A above with the work from Workstation C piling up in front of it. A diagram like this can serve as a temporary means for establishing common understanding of the process and the work flowing through it, and it becomes more clear how limiting the release of work can offer improvement in flow and the opportunity to catch our breath enough to improve the process itself.