The concept that keeping staff busy might be an ineffective way of managing will be so counterintuitive to many managers that further justification is probably needed.
There are several aspects to excessive WiP that are relevant to effectiveness, among them multi-tasking, context switching, focus, and long lead times.
Recent research on the brain has shown that one of the most expensive things your brain does (in terms of energy consumption) is changing tasks (Levitin,2015). Doing it constantly is draining and ineffective.
Focusing on one task, for periods of around 90 minutes at a time, enables your brain to get into the state known as flow. That’s when your most effective work gets done, and amazingly, it makes you feel good while tiring you out less.
Periods of flow are not your most creative periods, however. Focus is your brain’s mode when you“get things done,” but in your brain’s default mode, your mind flits between ideas. This is when you make connections between things and where creativity springs from. It is also where learning and long-term memories are created.
To be effective, you need time at work to be in both these modes; constant pressure with multiple unfinished tasks is damaging to both modes and results in poorer outcomes. For more on this topic, see (Benson, 2014).
Essential Kanban Condensed, Andy Carmichael and David J. Anderson, 2015
Read this book: Stop Starting, Start Finishing