Table 5.

Link between found measures and Lean Thinking.

Lean Thinking Concept	Found Measures	Clarification
Overproduction	-	-
Waiting	Time between process steps	Waiting can be expressed as time a patient is waiting between process steps.
Transport	-	-
Overprocessing	Duration of process steps	On a process step level, if a process step takes longer than necessary, the step is overprocessed.
	Number of certain process steps in trajectory	On a process trajectory level, if the trajectory consists of too many steps, too little steps, or the wrong steps, then there is overprocessing.
	Pathway/guidelines compliance or protocol utilization	On a value stream map level, if the compliance/utilization is low, the wrong steps or too little/many steps are performed.
Inventory	Number of patients in certain process steps/trajectory	Inventory is defined, among other things, as work in process (WIP). The number of patients that are in a certain part of the value stream map, patients in process, can be seen as stock at a process trajectory level.
Movement	-	-
Defects	Length of stay in hospital	The duration of hospitalization is often seen in medical literature as an outcome measure. A hospitalization that is longer than usual is regarded as a defect (an undesirable outcome).
	Percentage of cancellations	The cancellation of an appointment or another process step is an undesirable outcome and often needs a correction (rescheduling).
	Patient satisfaction	If a patient is not satisfied with the given care, it has an undesired outcome.
	Readmissions	If a patient needs to be readmitted, it means that rework is taking place.
	Complications	A complication is not the correct outcome of care. It leads to extra work and is a defect.
	Extra treatment needed or extra medication required	If additional treatment is required, the previous treatment has not had the correct outcome and rework is required.
	Pain scores	An unnecessarily high pain score is an undesired outcome.
	Mortality	The mortality is an undesirable outcome and thus a defect.
	Acute care utilization	A visit to the emergency department could be prevented by providing care earlier. Acute care utilization is undesirable and a defect.
	Functional recovery	Functional recovery indicates whether the desired outcome is met with the care process. If the recovery is worse than desired, this is a defect.
Flow	Duration of the whole trajectory	When flow occurs, patients move smoothly through the value stream map. The duration of the whole trajectory can be an indication of flow, where a shorter duration would indicate more flow.
Pull	-	-
No link	Identification of bottlenecks (long tasks commonly performed)	A bottleneck is defined here as a process step that takes a long time and is performed frequently. Identifying these bottlenecks can be used to level the process (heijunka) and thus create flow. But a bottleneck is not a quantification of flow itself.
	Treatment rate	The percentage that a certain treatment took place in the hospital is not a measure that can be linked to Lean Thinking in a clinical pathway.
	Count of wastes in process	Because this measure has no further specification on how it is counted, it cannot be linked to quantifying Lean Thinking.
	Number of staff interactions	In Lean Thinking there is no valuing of more or less staff interactions.
	Discharge to which location	The location to which a patient is discharged can be seen as an outcome measure, but it is outside the scope of the process within the hospital.
	Total cost	Cost is often a measure in Lean Thinking to express the effect of improvements but is not seen as one of the wastes.
	Cost reductions	Cost is often a measure in Lean Thinking to express the effect of improvements but is not seen as one of the wastes.