According to Kanban limiting Work In Progress is a foundational component that enables knowledge workers to engage in continuous improvement. But why? And how do I explain the need to limit WIP to execs and other decision makers that need to be convinced?
Here's the arguments I've been presenting..
Limiting WIP leads to a virtuous cycle of improvement. Multi tasking goes down, feedback goes up, errors are easier to catch, work becomes easier to break up into smaller prices, which makes it easier to limit WIP, which mean multi tasking goes down, etc, etc,etc
Limiting WIP is extremely important to ensuring maximum throughput in any systems that face variability. This has been proven in relatively stable systems like manufacturing assembly lines. It's exponentially more true in dynamic systems like software delivery and integration. Think of a highway, when WIP is to high you get a traffic jam, at the same time ifthe highway is empty you get no throughput, there is an optimization at play here. But this is a bell curve, 100 full WIP is never the answer
Limiting WIP exposes bottlenecks in your process, when inventory is low, and a particular process becomes blocked or produces defective work, it causes downstream processes to become starved of work. This is a good thing, it's a signal to fix your system of work. Yes, work will be delayed in the short term, but only long enough to improve the system of work, which will accelerate throughput over time.