Dominica DeGrandis describes five patterns that steal time from teams and offers ways to visualize the theft for improved decision making. youtube 
YOUTUBE -TGJePmaaas Dominica DeGrandis: Time Theft: How Hidden and Unplanned Work Commit the Perfect Crime
The five time thieves
Unplanned work
Neglected work
Unknown dependencies
Conflicting priorities
Too much Work in Progress (WIP)
WIP is a leading indicator
See Little’s Law wikipedia re: queuing theory
"We don’t let our servers reach 100% capacity, why do we let people reach 100% utilization?"
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I appreciate DeGrandis' applications of kanban to make these things visible. However, I challenge the premise particularly around unplanned work. This may be precisely where innovation is born.
When the next step is obvious and the obvious solution works then development proceeds at a predictable tempo. When the tempo pauses, it is enough to ask, what happened to the obvious solutions?